1
0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-22 10:42:39 +01:00
llvm-mirror/test/Other/new-pass-manager.ll

502 lines
29 KiB
LLVM
Raw Normal View History

; This test is essentially doing very basic things with the opt tool and the
; new pass manager pipeline. It will be used to flesh out the feature
; completeness of the opt tool when the new pass manager is engaged. The tests
; may not be useful once it becomes the default or may get spread out into other
; files, but for now this is just going to step the new process through its
; paces.
; RUN: opt -disable-output -disable-verify -debug-pass-manager \
; RUN: -passes=no-op-module %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-MODULE-PASS
; CHECK-MODULE-PASS: Starting llvm::Module pass manager run
; CHECK-MODULE-PASS-NEXT: Running pass: NoOpModulePass
; CHECK-MODULE-PASS-NEXT: Finished llvm::Module pass manager run
; RUN: opt -disable-output -disable-verify -debug-pass-manager \
; RUN: -passes=no-op-cgscc %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-CGSCC-PASS
; RUN: opt -disable-output -disable-verify -debug-pass-manager \
; RUN: -passes='cgscc(no-op-cgscc)' %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-CGSCC-PASS
; CHECK-CGSCC-PASS: Starting llvm::Module pass manager run
; CHECK-CGSCC-PASS-NEXT: Running pass: ModuleToPostOrderCGSCCPassAdaptor
; CHECK-CGSCC-PASS-NEXT: Running analysis: InnerAnalysisManagerProxy<{{.*(CGSCCAnalysisManager|AnalysisManager<.*LazyCallGraph::SCC.*>).*}},{{.*}}Module>
; CHECK-CGSCC-PASS-NEXT: Running analysis: InnerAnalysisManagerProxy<{{.*(FunctionAnalysisManager|AnalysisManager<.*Function.*>).*}},{{.*}}Module>
; CHECK-CGSCC-PASS-NEXT: Running analysis: LazyCallGraphAnalysis
; CHECK-CGSCC-PASS-NEXT: Running analysis: TargetLibraryAnalysis
[New PM] Introducing PassInstrumentation framework Pass Execution Instrumentation interface enables customizable instrumentation of pass execution, as per "RFC: Pass Execution Instrumentation interface" posted 06/07/2018 on llvm-dev@ The intent is to provide a common machinery to implement all the pass-execution-debugging features like print-before/after, opt-bisect, time-passes etc. Here we get a basic implementation consisting of: * PassInstrumentationCallbacks class that handles registration of callbacks and access to them. * PassInstrumentation class that handles instrumentation-point interfaces that call into PassInstrumentationCallbacks. * Callbacks accept StringRef which is just a name of the Pass right now. There were some ideas to pass an opaque wrapper for the pointer to pass instance, however it appears that pointer does not actually identify the instance (adaptors and managers might have the same address with the pass they govern). Hence it was decided to go simple for now and then later decide on what the proper mental model of identifying a "pass in a phase of pipeline" is. * Callbacks accept llvm::Any serving as a wrapper for const IRUnit*, to remove direct dependencies on different IRUnits (e.g. Analyses). * PassInstrumentationAnalysis analysis is explicitly requested from PassManager through usual AnalysisManager::getResult. All pass managers were updated to run that to get PassInstrumentation object for instrumentation calls. * Using tuples/index_sequence getAnalysisResult helper to extract generic AnalysisManager's extra args out of a generic PassManager's extra args. This is the only way I was able to explicitly run getResult for PassInstrumentationAnalysis out of a generic code like PassManager::run or RepeatedPass::run. TODO: Upon lengthy discussions we agreed to accept this as an initial implementation and then get rid of getAnalysisResult by improving RepeatedPass implementation. * PassBuilder takes PassInstrumentationCallbacks object to pass it further into PassInstrumentationAnalysis. Callbacks registration should be performed directly through PassInstrumentationCallbacks. * new-pm tests updated to account for PassInstrumentationAnalysis being run * Added PassInstrumentation tests to PassBuilderCallbacks unit tests. Other unit tests updated with registration of the now-required PassInstrumentationAnalysis. Made getName helper to return std::string (instead of StringRef initially) to fix asan builtbot failures on CGSCC tests. Reviewers: chandlerc, philip.pfaffe Differential Revision: https://reviews.llvm.org/D47858 llvm-svn: 342664
2018-09-20 19:08:45 +02:00
; CHECK-CGSCC-PASS-NEXT: Running analysis: PassInstrumentationAnalysis
[PM] Introduce basic update capabilities to the new PM's CGSCC pass manager, including both plumbing and logic to handle function pass updates. There are three fundamentally tied changes here: 1) Plumbing *some* mechanism for updating the CGSCC pass manager as the CG changes while passes are running. 2) Changing the CGSCC pass manager infrastructure to have support for the underlying graph to mutate mid-pass run. 3) Actually updating the CG after function passes run. I can separate them if necessary, but I think its really useful to have them together as the needs of #3 drove #2, and that in turn drove #1. The plumbing technique is to extend the "run" method signature with extra arguments. We provide the call graph that intrinsically is available as it is the basis of the pass manager's IR units, and an output parameter that records the results of updating the call graph during an SCC passes's run. Note that "...UpdateResult" isn't a *great* name here... suggestions very welcome. I tried a pretty frustrating number of different data structures and such for the innards of the update result. Every other one failed for one reason or another. Sometimes I just couldn't keep the layers of complexity right in my head. The thing that really worked was to just directly provide access to the underlying structures used to walk the call graph so that their updates could be informed by the *particular* nature of the change to the graph. The technique for how to make the pass management infrastructure cope with mutating graphs was also something that took a really, really large number of iterations to get to a place where I was happy. Here are some of the considerations that drove the design: - We operate at three levels within the infrastructure: RefSCC, SCC, and Node. In each case, we are working bottom up and so we want to continue to iterate on the "lowest" node as the graph changes. Look at how we iterate over nodes in an SCC running function passes as those function passes mutate the CG. We continue to iterate on the "lowest" SCC, which is the one that continues to contain the function just processed. - The call graph structure re-uses SCCs (and RefSCCs) during mutation events for the *highest* entry in the resulting new subgraph, not the lowest. This means that it is necessary to continually update the current SCC or RefSCC as it shifts. This is really surprising and subtle, and took a long time for me to work out. I actually tried changing the call graph to provide the opposite behavior, and it breaks *EVERYTHING*. The graph update algorithms are really deeply tied to this particualr pattern. - When SCCs or RefSCCs are split apart and refined and we continually re-pin our processing to the bottom one in the subgraph, we need to enqueue the newly formed SCCs and RefSCCs for subsequent processing. Queuing them presents a few challenges: 1) SCCs and RefSCCs use wildly different iteration strategies at a high level. We end up needing to converge them on worklist approaches that can be extended in order to be able to handle the mutations. 2) The order of the enqueuing need to remain bottom-up post-order so that we don't get surprising order of visitation for things like the inliner. 3) We need the worklists to have set semantics so we don't duplicate things endlessly. We don't need a *persistent* set though because we always keep processing the bottom node!!!! This is super, super surprising to me and took a long time to convince myself this is correct, but I'm pretty sure it is... Once we sink down to the bottom node, we can't re-split out the same node in any way, and the postorder of the current queue is fixed and unchanging. 4) We need to make sure that the "current" SCC or RefSCC actually gets enqueued here such that we re-visit it because we continue processing a *new*, *bottom* SCC/RefSCC. - We also need the ability to *skip* SCCs and RefSCCs that get merged into a larger component. We even need the ability to skip *nodes* from an SCC that are no longer part of that SCC. This led to the design you see in the patch which uses SetVector-based worklists. The RefSCC worklist is always empty until an update occurs and is just used to handle those RefSCCs created by updates as the others don't even exist yet and are formed on-demand during the bottom-up walk. The SCC worklist is pre-populated from the RefSCC, and we push new SCCs onto it and blacklist existing SCCs on it to get the desired processing. We then *directly* update these when updating the call graph as I was never able to find a satisfactory abstraction around the update strategy. Finally, we need to compute the updates for function passes. This is mostly used as an initial customer of all the update mechanisms to drive their design to at least cover some real set of use cases. There are a bunch of interesting things that came out of doing this: - It is really nice to do this a function at a time because that function is likely hot in the cache. This means we want even the function pass adaptor to support online updates to the call graph! - To update the call graph after arbitrary function pass mutations is quite hard. We have to build a fairly comprehensive set of data structures and then process them. Fortunately, some of this code is related to the code for building the cal graph in the first place. Unfortunately, very little of it makes any sense to share because the nature of what we're doing is so very different. I've factored out the one part that made sense at least. - We need to transfer these updates into the various structures for the CGSCC pass manager. Once those were more sanely worked out, this became relatively easier. But some of those needs necessitated changes to the LazyCallGraph interface to make it significantly easier to extract the changed SCCs from an update operation. - We also need to update the CGSCC analysis manager as the shape of the graph changes. When an SCC is merged away we need to clear analyses associated with it from the analysis manager which we didn't have support for in the analysis manager infrsatructure. New SCCs are easy! But then we have the case that the original SCC has its shape changed but remains in the call graph. There we need to *invalidate* the analyses associated with it. - We also need to invalidate analyses after we *finish* processing an SCC. But the analyses we need to invalidate here are *only those for the newly updated SCC*!!! Because we only continue processing the bottom SCC, if we split SCCs apart the original one gets invalidated once when its shape changes and is not processed farther so its analyses will be correct. It is the bottom SCC which continues being processed and needs to have the "normal" invalidation done based on the preserved analyses set. All of this is mostly background and context for the changes here. Many thanks to all the reviewers who helped here. Especially Sanjoy who caught several interesting bugs in the graph algorithms, David, Sean, and others who all helped with feedback. Differential Revision: http://reviews.llvm.org/D21464 llvm-svn: 279618
2016-08-24 11:37:14 +02:00
; CHECK-CGSCC-PASS-NEXT: Starting CGSCC pass manager run
; CHECK-CGSCC-PASS-NEXT: Running pass: NoOpCGSCCPass
[PM] Introduce basic update capabilities to the new PM's CGSCC pass manager, including both plumbing and logic to handle function pass updates. There are three fundamentally tied changes here: 1) Plumbing *some* mechanism for updating the CGSCC pass manager as the CG changes while passes are running. 2) Changing the CGSCC pass manager infrastructure to have support for the underlying graph to mutate mid-pass run. 3) Actually updating the CG after function passes run. I can separate them if necessary, but I think its really useful to have them together as the needs of #3 drove #2, and that in turn drove #1. The plumbing technique is to extend the "run" method signature with extra arguments. We provide the call graph that intrinsically is available as it is the basis of the pass manager's IR units, and an output parameter that records the results of updating the call graph during an SCC passes's run. Note that "...UpdateResult" isn't a *great* name here... suggestions very welcome. I tried a pretty frustrating number of different data structures and such for the innards of the update result. Every other one failed for one reason or another. Sometimes I just couldn't keep the layers of complexity right in my head. The thing that really worked was to just directly provide access to the underlying structures used to walk the call graph so that their updates could be informed by the *particular* nature of the change to the graph. The technique for how to make the pass management infrastructure cope with mutating graphs was also something that took a really, really large number of iterations to get to a place where I was happy. Here are some of the considerations that drove the design: - We operate at three levels within the infrastructure: RefSCC, SCC, and Node. In each case, we are working bottom up and so we want to continue to iterate on the "lowest" node as the graph changes. Look at how we iterate over nodes in an SCC running function passes as those function passes mutate the CG. We continue to iterate on the "lowest" SCC, which is the one that continues to contain the function just processed. - The call graph structure re-uses SCCs (and RefSCCs) during mutation events for the *highest* entry in the resulting new subgraph, not the lowest. This means that it is necessary to continually update the current SCC or RefSCC as it shifts. This is really surprising and subtle, and took a long time for me to work out. I actually tried changing the call graph to provide the opposite behavior, and it breaks *EVERYTHING*. The graph update algorithms are really deeply tied to this particualr pattern. - When SCCs or RefSCCs are split apart and refined and we continually re-pin our processing to the bottom one in the subgraph, we need to enqueue the newly formed SCCs and RefSCCs for subsequent processing. Queuing them presents a few challenges: 1) SCCs and RefSCCs use wildly different iteration strategies at a high level. We end up needing to converge them on worklist approaches that can be extended in order to be able to handle the mutations. 2) The order of the enqueuing need to remain bottom-up post-order so that we don't get surprising order of visitation for things like the inliner. 3) We need the worklists to have set semantics so we don't duplicate things endlessly. We don't need a *persistent* set though because we always keep processing the bottom node!!!! This is super, super surprising to me and took a long time to convince myself this is correct, but I'm pretty sure it is... Once we sink down to the bottom node, we can't re-split out the same node in any way, and the postorder of the current queue is fixed and unchanging. 4) We need to make sure that the "current" SCC or RefSCC actually gets enqueued here such that we re-visit it because we continue processing a *new*, *bottom* SCC/RefSCC. - We also need the ability to *skip* SCCs and RefSCCs that get merged into a larger component. We even need the ability to skip *nodes* from an SCC that are no longer part of that SCC. This led to the design you see in the patch which uses SetVector-based worklists. The RefSCC worklist is always empty until an update occurs and is just used to handle those RefSCCs created by updates as the others don't even exist yet and are formed on-demand during the bottom-up walk. The SCC worklist is pre-populated from the RefSCC, and we push new SCCs onto it and blacklist existing SCCs on it to get the desired processing. We then *directly* update these when updating the call graph as I was never able to find a satisfactory abstraction around the update strategy. Finally, we need to compute the updates for function passes. This is mostly used as an initial customer of all the update mechanisms to drive their design to at least cover some real set of use cases. There are a bunch of interesting things that came out of doing this: - It is really nice to do this a function at a time because that function is likely hot in the cache. This means we want even the function pass adaptor to support online updates to the call graph! - To update the call graph after arbitrary function pass mutations is quite hard. We have to build a fairly comprehensive set of data structures and then process them. Fortunately, some of this code is related to the code for building the cal graph in the first place. Unfortunately, very little of it makes any sense to share because the nature of what we're doing is so very different. I've factored out the one part that made sense at least. - We need to transfer these updates into the various structures for the CGSCC pass manager. Once those were more sanely worked out, this became relatively easier. But some of those needs necessitated changes to the LazyCallGraph interface to make it significantly easier to extract the changed SCCs from an update operation. - We also need to update the CGSCC analysis manager as the shape of the graph changes. When an SCC is merged away we need to clear analyses associated with it from the analysis manager which we didn't have support for in the analysis manager infrsatructure. New SCCs are easy! But then we have the case that the original SCC has its shape changed but remains in the call graph. There we need to *invalidate* the analyses associated with it. - We also need to invalidate analyses after we *finish* processing an SCC. But the analyses we need to invalidate here are *only those for the newly updated SCC*!!! Because we only continue processing the bottom SCC, if we split SCCs apart the original one gets invalidated once when its shape changes and is not processed farther so its analyses will be correct. It is the bottom SCC which continues being processed and needs to have the "normal" invalidation done based on the preserved analyses set. All of this is mostly background and context for the changes here. Many thanks to all the reviewers who helped here. Especially Sanjoy who caught several interesting bugs in the graph algorithms, David, Sean, and others who all helped with feedback. Differential Revision: http://reviews.llvm.org/D21464 llvm-svn: 279618
2016-08-24 11:37:14 +02:00
; CHECK-CGSCC-PASS-NEXT: Finished CGSCC pass manager run
; CHECK-CGSCC-PASS-NEXT: Finished llvm::Module pass manager run
; RUN: opt -disable-output -disable-verify -debug-pass-manager \
; RUN: -passes=no-op-function %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-FUNCTION-PASS
; RUN: opt -disable-output -disable-verify -debug-pass-manager \
; RUN: -passes='function(no-op-function)' %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-FUNCTION-PASS
; CHECK-FUNCTION-PASS: Starting llvm::Module pass manager run
; CHECK-FUNCTION-PASS-NEXT: Running pass: ModuleToFunctionPassAdaptor
; CHECK-FUNCTION-PASS-NEXT: Running analysis: InnerAnalysisManagerProxy<{{.*}}>
[New PM] Introducing PassInstrumentation framework Pass Execution Instrumentation interface enables customizable instrumentation of pass execution, as per "RFC: Pass Execution Instrumentation interface" posted 06/07/2018 on llvm-dev@ The intent is to provide a common machinery to implement all the pass-execution-debugging features like print-before/after, opt-bisect, time-passes etc. Here we get a basic implementation consisting of: * PassInstrumentationCallbacks class that handles registration of callbacks and access to them. * PassInstrumentation class that handles instrumentation-point interfaces that call into PassInstrumentationCallbacks. * Callbacks accept StringRef which is just a name of the Pass right now. There were some ideas to pass an opaque wrapper for the pointer to pass instance, however it appears that pointer does not actually identify the instance (adaptors and managers might have the same address with the pass they govern). Hence it was decided to go simple for now and then later decide on what the proper mental model of identifying a "pass in a phase of pipeline" is. * Callbacks accept llvm::Any serving as a wrapper for const IRUnit*, to remove direct dependencies on different IRUnits (e.g. Analyses). * PassInstrumentationAnalysis analysis is explicitly requested from PassManager through usual AnalysisManager::getResult. All pass managers were updated to run that to get PassInstrumentation object for instrumentation calls. * Using tuples/index_sequence getAnalysisResult helper to extract generic AnalysisManager's extra args out of a generic PassManager's extra args. This is the only way I was able to explicitly run getResult for PassInstrumentationAnalysis out of a generic code like PassManager::run or RepeatedPass::run. TODO: Upon lengthy discussions we agreed to accept this as an initial implementation and then get rid of getAnalysisResult by improving RepeatedPass implementation. * PassBuilder takes PassInstrumentationCallbacks object to pass it further into PassInstrumentationAnalysis. Callbacks registration should be performed directly through PassInstrumentationCallbacks. * new-pm tests updated to account for PassInstrumentationAnalysis being run * Added PassInstrumentation tests to PassBuilderCallbacks unit tests. Other unit tests updated with registration of the now-required PassInstrumentationAnalysis. Made getName helper to return std::string (instead of StringRef initially) to fix asan builtbot failures on CGSCC tests. Reviewers: chandlerc, philip.pfaffe Differential Revision: https://reviews.llvm.org/D47858 llvm-svn: 342664
2018-09-20 19:08:45 +02:00
; CHECK-FUNCTION-PASS-NEXT: Running analysis: PassInstrumentationAnalysis
; CHECK-FUNCTION-PASS-NEXT: Starting llvm::Function pass manager run
; CHECK-FUNCTION-PASS-NEXT: Running pass: NoOpFunctionPass
; CHECK-FUNCTION-PASS-NEXT: Finished llvm::Function pass manager run
; CHECK-FUNCTION-PASS-NEXT: Finished llvm::Module pass manager run
; RUN: opt -disable-output -debug-pass-manager -passes=print %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-MODULE-PRINT
; CHECK-MODULE-PRINT: Starting llvm::Module pass manager run
; CHECK-MODULE-PRINT: Running pass: VerifierPass
; CHECK-MODULE-PRINT: Running pass: PrintModulePass
; CHECK-MODULE-PRINT: ModuleID
; CHECK-MODULE-PRINT: define void @foo(i1 %x, i8* %p1, i8* %p2)
; CHECK-MODULE-PRINT: Running pass: VerifierPass
; CHECK-MODULE-PRINT: Finished llvm::Module pass manager run
; RUN: opt -disable-output -debug-pass-manager -disable-verify -passes='print,verify' %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-MODULE-VERIFY
; CHECK-MODULE-VERIFY: Starting llvm::Module pass manager run
; CHECK-MODULE-VERIFY: Running pass: PrintModulePass
; CHECK-MODULE-VERIFY: ModuleID
; CHECK-MODULE-VERIFY: define void @foo(i1 %x, i8* %p1, i8* %p2)
; CHECK-MODULE-VERIFY: Running pass: VerifierPass
; CHECK-MODULE-VERIFY: Finished llvm::Module pass manager run
; RUN: opt -disable-output -debug-pass-manager -passes='function(print)' %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-FUNCTION-PRINT
; CHECK-FUNCTION-PRINT: Starting llvm::Module pass manager run
; CHECK-FUNCTION-PRINT: Running pass: VerifierPass
; CHECK-FUNCTION-PRINT: Running pass: ModuleToFunctionPassAdaptor
; CHECK-FUNCTION-PRINT: Running analysis: InnerAnalysisManagerProxy<{{.*}}>
; CHECK-FUNCTION-PRINT: Starting llvm::Function pass manager run
; CHECK-FUNCTION-PRINT: Running pass: PrintFunctionPass
; CHECK-FUNCTION-PRINT-NOT: ModuleID
; CHECK-FUNCTION-PRINT: define void @foo(i1 %x, i8* %p1, i8* %p2)
; CHECK-FUNCTION-PRINT: Finished llvm::Function pass manager run
; CHECK-FUNCTION-PRINT: Running pass: VerifierPass
; CHECK-FUNCTION-PRINT: Finished llvm::Module pass manager run
; RUN: opt -disable-output -debug-pass-manager -disable-verify -passes='function(print,verify)' %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-FUNCTION-VERIFY
; CHECK-FUNCTION-VERIFY: Starting llvm::Module pass manager run
; CHECK-FUNCTION-VERIFY: Starting llvm::Function pass manager run
; CHECK-FUNCTION-VERIFY: Running pass: PrintFunctionPass
; CHECK-FUNCTION-VERIFY-NOT: ModuleID
; CHECK-FUNCTION-VERIFY: define void @foo(i1 %x, i8* %p1, i8* %p2)
; CHECK-FUNCTION-VERIFY: Running pass: VerifierPass
; CHECK-FUNCTION-VERIFY: Finished llvm::Function pass manager run
; CHECK-FUNCTION-VERIFY: Finished llvm::Module pass manager run
; RUN: opt -S -o - -passes='no-op-module,no-op-module' %s \
; RUN: | FileCheck %s --check-prefix=CHECK-NOOP
; CHECK-NOOP: define void @foo(i1 %x, i8* %p1, i8* %p2) {
; CHECK-NOOP: entry:
; CHECK-NOOP: store i8 42, i8* %p1
; CHECK-NOOP: br i1 %x, label %loop, label %exit
; CHECK-NOOP: loop:
; CHECK-NOOP: %tmp1 = load i8, i8* %p2
; CHECK-NOOP: br label %loop
; CHECK-NOOP: exit:
; CHECK-NOOP: ret void
; CHECK-NOOP: }
; Round trip through bitcode.
; RUN: opt -f -o - -passes='no-op-module,no-op-module' %s \
; RUN: | llvm-dis \
; RUN: | FileCheck %s --check-prefix=CHECK-NOOP
; RUN: opt -disable-output -debug-pass-manager -verify-each -passes='no-op-module,function(no-op-function)' %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-VERIFY-EACH
; CHECK-VERIFY-EACH: Starting llvm::Module pass manager run
; CHECK-VERIFY-EACH: Running pass: VerifierPass
; CHECK-VERIFY-EACH: Running pass: NoOpModulePass
; CHECK-VERIFY-EACH: Running pass: VerifierPass
; CHECK-VERIFY-EACH: Starting llvm::Function pass manager run
; CHECK-VERIFY-EACH: Running pass: NoOpFunctionPass
; CHECK-VERIFY-EACH: Running pass: VerifierPass
; CHECK-VERIFY-EACH: Finished llvm::Function pass manager run
; CHECK-VERIFY-EACH: Running pass: VerifierPass
; CHECK-VERIFY-EACH: Finished llvm::Module pass manager run
; RUN: opt -disable-output -debug-pass-manager -disable-verify -passes='no-op-module,function(no-op-function)' %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-NO-VERIFY
; CHECK-NO-VERIFY: Starting llvm::Module pass manager run
; CHECK-NO-VERIFY-NOT: VerifierPass
; CHECK-NO-VERIFY: Running pass: NoOpModulePass
; CHECK-NO-VERIFY-NOT: VerifierPass
; CHECK-NO-VERIFY: Starting llvm::Function pass manager run
; CHECK-NO-VERIFY: Running pass: NoOpFunctionPass
; CHECK-NO-VERIFY-NOT: VerifierPass
; CHECK-NO-VERIFY: Finished llvm::Function pass manager run
; CHECK-NO-VERIFY-NOT: VerifierPass
; CHECK-NO-VERIFY: Finished llvm::Module pass manager run
; RUN: opt -disable-output -debug-pass-manager \
; RUN: -passes='require<no-op-module>,cgscc(require<no-op-cgscc>,function(require<no-op-function>))' %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-ANALYSES
; CHECK-ANALYSES: Starting llvm::Module pass manager run
; CHECK-ANALYSES: Running pass: RequireAnalysisPass
; CHECK-ANALYSES: Running analysis: NoOpModuleAnalysis
[PM] Introduce basic update capabilities to the new PM's CGSCC pass manager, including both plumbing and logic to handle function pass updates. There are three fundamentally tied changes here: 1) Plumbing *some* mechanism for updating the CGSCC pass manager as the CG changes while passes are running. 2) Changing the CGSCC pass manager infrastructure to have support for the underlying graph to mutate mid-pass run. 3) Actually updating the CG after function passes run. I can separate them if necessary, but I think its really useful to have them together as the needs of #3 drove #2, and that in turn drove #1. The plumbing technique is to extend the "run" method signature with extra arguments. We provide the call graph that intrinsically is available as it is the basis of the pass manager's IR units, and an output parameter that records the results of updating the call graph during an SCC passes's run. Note that "...UpdateResult" isn't a *great* name here... suggestions very welcome. I tried a pretty frustrating number of different data structures and such for the innards of the update result. Every other one failed for one reason or another. Sometimes I just couldn't keep the layers of complexity right in my head. The thing that really worked was to just directly provide access to the underlying structures used to walk the call graph so that their updates could be informed by the *particular* nature of the change to the graph. The technique for how to make the pass management infrastructure cope with mutating graphs was also something that took a really, really large number of iterations to get to a place where I was happy. Here are some of the considerations that drove the design: - We operate at three levels within the infrastructure: RefSCC, SCC, and Node. In each case, we are working bottom up and so we want to continue to iterate on the "lowest" node as the graph changes. Look at how we iterate over nodes in an SCC running function passes as those function passes mutate the CG. We continue to iterate on the "lowest" SCC, which is the one that continues to contain the function just processed. - The call graph structure re-uses SCCs (and RefSCCs) during mutation events for the *highest* entry in the resulting new subgraph, not the lowest. This means that it is necessary to continually update the current SCC or RefSCC as it shifts. This is really surprising and subtle, and took a long time for me to work out. I actually tried changing the call graph to provide the opposite behavior, and it breaks *EVERYTHING*. The graph update algorithms are really deeply tied to this particualr pattern. - When SCCs or RefSCCs are split apart and refined and we continually re-pin our processing to the bottom one in the subgraph, we need to enqueue the newly formed SCCs and RefSCCs for subsequent processing. Queuing them presents a few challenges: 1) SCCs and RefSCCs use wildly different iteration strategies at a high level. We end up needing to converge them on worklist approaches that can be extended in order to be able to handle the mutations. 2) The order of the enqueuing need to remain bottom-up post-order so that we don't get surprising order of visitation for things like the inliner. 3) We need the worklists to have set semantics so we don't duplicate things endlessly. We don't need a *persistent* set though because we always keep processing the bottom node!!!! This is super, super surprising to me and took a long time to convince myself this is correct, but I'm pretty sure it is... Once we sink down to the bottom node, we can't re-split out the same node in any way, and the postorder of the current queue is fixed and unchanging. 4) We need to make sure that the "current" SCC or RefSCC actually gets enqueued here such that we re-visit it because we continue processing a *new*, *bottom* SCC/RefSCC. - We also need the ability to *skip* SCCs and RefSCCs that get merged into a larger component. We even need the ability to skip *nodes* from an SCC that are no longer part of that SCC. This led to the design you see in the patch which uses SetVector-based worklists. The RefSCC worklist is always empty until an update occurs and is just used to handle those RefSCCs created by updates as the others don't even exist yet and are formed on-demand during the bottom-up walk. The SCC worklist is pre-populated from the RefSCC, and we push new SCCs onto it and blacklist existing SCCs on it to get the desired processing. We then *directly* update these when updating the call graph as I was never able to find a satisfactory abstraction around the update strategy. Finally, we need to compute the updates for function passes. This is mostly used as an initial customer of all the update mechanisms to drive their design to at least cover some real set of use cases. There are a bunch of interesting things that came out of doing this: - It is really nice to do this a function at a time because that function is likely hot in the cache. This means we want even the function pass adaptor to support online updates to the call graph! - To update the call graph after arbitrary function pass mutations is quite hard. We have to build a fairly comprehensive set of data structures and then process them. Fortunately, some of this code is related to the code for building the cal graph in the first place. Unfortunately, very little of it makes any sense to share because the nature of what we're doing is so very different. I've factored out the one part that made sense at least. - We need to transfer these updates into the various structures for the CGSCC pass manager. Once those were more sanely worked out, this became relatively easier. But some of those needs necessitated changes to the LazyCallGraph interface to make it significantly easier to extract the changed SCCs from an update operation. - We also need to update the CGSCC analysis manager as the shape of the graph changes. When an SCC is merged away we need to clear analyses associated with it from the analysis manager which we didn't have support for in the analysis manager infrsatructure. New SCCs are easy! But then we have the case that the original SCC has its shape changed but remains in the call graph. There we need to *invalidate* the analyses associated with it. - We also need to invalidate analyses after we *finish* processing an SCC. But the analyses we need to invalidate here are *only those for the newly updated SCC*!!! Because we only continue processing the bottom SCC, if we split SCCs apart the original one gets invalidated once when its shape changes and is not processed farther so its analyses will be correct. It is the bottom SCC which continues being processed and needs to have the "normal" invalidation done based on the preserved analyses set. All of this is mostly background and context for the changes here. Many thanks to all the reviewers who helped here. Especially Sanjoy who caught several interesting bugs in the graph algorithms, David, Sean, and others who all helped with feedback. Differential Revision: http://reviews.llvm.org/D21464 llvm-svn: 279618
2016-08-24 11:37:14 +02:00
; CHECK-ANALYSES: Starting CGSCC pass manager run
; CHECK-ANALYSES: Running pass: RequireAnalysisPass
; CHECK-ANALYSES: Running analysis: NoOpCGSCCAnalysis
; CHECK-ANALYSES: Starting llvm::Function pass manager run
; CHECK-ANALYSES: Running pass: RequireAnalysisPass
; CHECK-ANALYSES: Running analysis: NoOpFunctionAnalysis
; Make sure no-op passes that preserve all analyses don't even try to do any
; analysis invalidation.
; RUN: opt -disable-output -debug-pass-manager \
; RUN: -passes='require<no-op-module>,cgscc(require<no-op-cgscc>,function(require<no-op-function>))' %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-NO-OP-INVALIDATION
; CHECK-NO-OP-INVALIDATION: Starting llvm::Module pass manager run
; CHECK-NO-OP-INVALIDATION-NOT: Invalidating all non-preserved analyses
; RUN: opt -disable-output -debug-pass-manager \
; RUN: -passes='require<no-op-module>,require<no-op-module>,require<no-op-module>' %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-DO-CACHE-MODULE-ANALYSIS-RESULTS
; CHECK-DO-CACHE-MODULE-ANALYSIS-RESULTS: Starting llvm::Module pass manager run
; CHECK-DO-CACHE-MODULE-ANALYSIS-RESULTS: Running pass: RequireAnalysisPass
; CHECK-DO-CACHE-MODULE-ANALYSIS-RESULTS: Running analysis: NoOpModuleAnalysis
; CHECK-DO-CACHE-MODULE-ANALYSIS-RESULTS-NOT: Running analysis: NoOpModuleAnalysis
; RUN: opt -disable-output -debug-pass-manager \
; RUN: -passes='require<no-op-module>,invalidate<no-op-module>,require<no-op-module>' %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-DO-INVALIDATE-MODULE-ANALYSIS-RESULTS
; CHECK-DO-INVALIDATE-MODULE-ANALYSIS-RESULTS: Starting llvm::Module pass manager run
; CHECK-DO-INVALIDATE-MODULE-ANALYSIS-RESULTS: Running pass: RequireAnalysisPass
; CHECK-DO-INVALIDATE-MODULE-ANALYSIS-RESULTS: Running analysis: NoOpModuleAnalysis
; CHECK-DO-INVALIDATE-MODULE-ANALYSIS-RESULTS: Invalidating analysis: NoOpModuleAnalysis
; CHECK-DO-INVALIDATE-MODULE-ANALYSIS-RESULTS: Running analysis: NoOpModuleAnalysis
; RUN: opt -disable-output -debug-pass-manager \
; RUN: -passes='cgscc(require<no-op-cgscc>,require<no-op-cgscc>,require<no-op-cgscc>)' %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-DO-CACHE-CGSCC-ANALYSIS-RESULTS
; CHECK-DO-CACHE-CGSCC-ANALYSIS-RESULTS: Starting llvm::Module pass manager run
; CHECK-DO-CACHE-CGSCC-ANALYSIS-RESULTS: Running pass: RequireAnalysisPass
; CHECK-DO-CACHE-CGSCC-ANALYSIS-RESULTS: Running analysis: NoOpCGSCCAnalysis
; CHECK-DO-CACHE-CGSCC-ANALYSIS-RESULTS-NOT: Running analysis: NoOpCGSCCAnalysis
; RUN: opt -disable-output -debug-pass-manager \
; RUN: -passes='cgscc(require<no-op-cgscc>,invalidate<no-op-cgscc>,require<no-op-cgscc>)' %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-DO-INVALIDATE-CGSCC-ANALYSIS-RESULTS
; CHECK-DO-INVALIDATE-CGSCC-ANALYSIS-RESULTS: Starting llvm::Module pass manager run
; CHECK-DO-INVALIDATE-CGSCC-ANALYSIS-RESULTS: Running pass: RequireAnalysisPass
; CHECK-DO-INVALIDATE-CGSCC-ANALYSIS-RESULTS: Running analysis: NoOpCGSCCAnalysis
; CHECK-DO-INVALIDATE-CGSCC-ANALYSIS-RESULTS: Invalidating analysis: NoOpCGSCCAnalysis
; CHECK-DO-INVALIDATE-CGSCC-ANALYSIS-RESULTS: Running analysis: NoOpCGSCCAnalysis
; RUN: opt -disable-output -debug-pass-manager \
; RUN: -passes='function(require<no-op-function>,require<no-op-function>,require<no-op-function>)' %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-DO-CACHE-FUNCTION-ANALYSIS-RESULTS
; CHECK-DO-CACHE-FUNCTION-ANALYSIS-RESULTS: Starting llvm::Module pass manager run
; CHECK-DO-CACHE-FUNCTION-ANALYSIS-RESULTS: Running pass: RequireAnalysisPass
; CHECK-DO-CACHE-FUNCTION-ANALYSIS-RESULTS: Running analysis: NoOpFunctionAnalysis
; CHECK-DO-CACHE-FUNCTION-ANALYSIS-RESULTS-NOT: Running analysis: NoOpFunctionAnalysis
; RUN: opt -disable-output -debug-pass-manager \
; RUN: -passes='function(require<no-op-function>,invalidate<no-op-function>,require<no-op-function>)' %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-DO-INVALIDATE-FUNCTION-ANALYSIS-RESULTS
; CHECK-DO-INVALIDATE-FUNCTION-ANALYSIS-RESULTS: Starting llvm::Module pass manager run
; CHECK-DO-INVALIDATE-FUNCTION-ANALYSIS-RESULTS: Running pass: RequireAnalysisPass
; CHECK-DO-INVALIDATE-FUNCTION-ANALYSIS-RESULTS: Running analysis: NoOpFunctionAnalysis
; CHECK-DO-INVALIDATE-FUNCTION-ANALYSIS-RESULTS: Invalidating analysis: NoOpFunctionAnalysis
; CHECK-DO-INVALIDATE-FUNCTION-ANALYSIS-RESULTS: Running analysis: NoOpFunctionAnalysis
; RUN: opt -disable-output -disable-verify -debug-pass-manager \
[PM] Fix a pretty nasty bug where the new pass manager would invalidate passes too many time. I think this is actually the issue that someone raised with me at the developer's meeting and in an email, but that we never really got to the bottom of. Having all the testing utilities made it much easier to dig down and uncover the core issue. When a pass manager is running many passes over a single function, we need it to invalidate the analyses between each run so that they can be re-computed as needed. We also need to track the intersection of preserved higher-level analyses across all the passes that we run (for example, if there is one module analysis which all the function analyses preserve, we want to track that and propagate it). Unfortunately, this interacted poorly with any enclosing pass adaptor between two IR units. It would see the intersection of preserved analyses, and need to invalidate any other analyses, but some of the un-preserved analyses might have already been invalidated *and recomputed*! We would fail to propagate the fact that the analysis had already been invalidated. The solution to this struck me as really strange at first, but the more I thought about it, the more natural it seemed. After a nice discussion with Duncan about it on IRC, it seemed even nicer. The idea is that invalidating an analysis *causes* it to be preserved! Preserving the lack of result is trivial. If it is recomputed, great. Until something *else* invalidates it again, we're good. The consequence of this is that the invalidate methods on the analysis manager which operate over many passes now consume their PreservedAnalyses object, update it to "preserve" every analysis pass to which it delivers an invalidation (regardless of whether the pass chooses to be removed, or handles the invalidation itself by updating itself). Then we return this augmented set from the invalidate routine, letting the pass manager take the result and use the intersection of *that* across each pass run to compute the final preserved set. This accounts for all the places where the early invalidation of an analysis has already "preserved" it for a future run. I've beefed up the testing and adjusted the assertions to show that we no longer repeatedly invalidate or compute the analyses across nested pass managers. llvm-svn: 225333
2015-01-07 02:58:35 +01:00
; RUN: -passes='require<no-op-module>,module(require<no-op-module>,function(require<no-op-function>,invalidate<all>,require<no-op-function>),require<no-op-module>),require<no-op-module>' %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-INVALIDATE-ALL
; CHECK-INVALIDATE-ALL: Starting llvm::Module pass manager run
; CHECK-INVALIDATE-ALL: Running pass: RequireAnalysisPass
; CHECK-INVALIDATE-ALL: Running analysis: NoOpModuleAnalysis
; CHECK-INVALIDATE-ALL: Starting llvm::Module pass manager run
; CHECK-INVALIDATE-ALL: Running pass: RequireAnalysisPass
; CHECK-INVALIDATE-ALL-NOT: Running analysis: NoOpModuleAnalysis
; CHECK-INVALIDATE-ALL: Starting llvm::Function pass manager run
; CHECK-INVALIDATE-ALL: Running pass: RequireAnalysisPass
; CHECK-INVALIDATE-ALL: Running analysis: NoOpFunctionAnalysis
; CHECK-INVALIDATE-ALL: Running pass: InvalidateAllAnalysesPass
; CHECK-INVALIDATE-ALL: Invalidating analysis: NoOpFunctionAnalysis
; CHECK-INVALIDATE-ALL: Running pass: RequireAnalysisPass
; CHECK-INVALIDATE-ALL: Running analysis: NoOpFunctionAnalysis
; CHECK-INVALIDATE-ALL: Finished llvm::Function pass manager run
; CHECK-INVALIDATE-ALL: Invalidating analysis: NoOpModuleAnalysis
; CHECK-INVALIDATE-ALL: Running pass: RequireAnalysisPass
; CHECK-INVALIDATE-ALL: Running analysis: NoOpModuleAnalysis
; CHECK-INVALIDATE-ALL: Finished llvm::Module pass manager run
; CHECK-INVALIDATE-ALL-NOT: Invalidating analysis: NoOpModuleAnalysis
; CHECK-INVALIDATE-ALL: Running pass: RequireAnalysisPass
; CHECK-INVALIDATE-ALL-NOT: Running analysis: NoOpModuleAnalysis
; CHECK-INVALIDATE-ALL: Finished llvm::Module pass manager run
[PM] Fix a pretty nasty bug where the new pass manager would invalidate passes too many time. I think this is actually the issue that someone raised with me at the developer's meeting and in an email, but that we never really got to the bottom of. Having all the testing utilities made it much easier to dig down and uncover the core issue. When a pass manager is running many passes over a single function, we need it to invalidate the analyses between each run so that they can be re-computed as needed. We also need to track the intersection of preserved higher-level analyses across all the passes that we run (for example, if there is one module analysis which all the function analyses preserve, we want to track that and propagate it). Unfortunately, this interacted poorly with any enclosing pass adaptor between two IR units. It would see the intersection of preserved analyses, and need to invalidate any other analyses, but some of the un-preserved analyses might have already been invalidated *and recomputed*! We would fail to propagate the fact that the analysis had already been invalidated. The solution to this struck me as really strange at first, but the more I thought about it, the more natural it seemed. After a nice discussion with Duncan about it on IRC, it seemed even nicer. The idea is that invalidating an analysis *causes* it to be preserved! Preserving the lack of result is trivial. If it is recomputed, great. Until something *else* invalidates it again, we're good. The consequence of this is that the invalidate methods on the analysis manager which operate over many passes now consume their PreservedAnalyses object, update it to "preserve" every analysis pass to which it delivers an invalidation (regardless of whether the pass chooses to be removed, or handles the invalidation itself by updating itself). Then we return this augmented set from the invalidate routine, letting the pass manager take the result and use the intersection of *that* across each pass run to compute the final preserved set. This accounts for all the places where the early invalidation of an analysis has already "preserved" it for a future run. I've beefed up the testing and adjusted the assertions to show that we no longer repeatedly invalidate or compute the analyses across nested pass managers. llvm-svn: 225333
2015-01-07 02:58:35 +01:00
; RUN: opt -disable-output -disable-verify -debug-pass-manager \
[PM] Fix a pretty nasty bug where the new pass manager would invalidate passes too many time. I think this is actually the issue that someone raised with me at the developer's meeting and in an email, but that we never really got to the bottom of. Having all the testing utilities made it much easier to dig down and uncover the core issue. When a pass manager is running many passes over a single function, we need it to invalidate the analyses between each run so that they can be re-computed as needed. We also need to track the intersection of preserved higher-level analyses across all the passes that we run (for example, if there is one module analysis which all the function analyses preserve, we want to track that and propagate it). Unfortunately, this interacted poorly with any enclosing pass adaptor between two IR units. It would see the intersection of preserved analyses, and need to invalidate any other analyses, but some of the un-preserved analyses might have already been invalidated *and recomputed*! We would fail to propagate the fact that the analysis had already been invalidated. The solution to this struck me as really strange at first, but the more I thought about it, the more natural it seemed. After a nice discussion with Duncan about it on IRC, it seemed even nicer. The idea is that invalidating an analysis *causes* it to be preserved! Preserving the lack of result is trivial. If it is recomputed, great. Until something *else* invalidates it again, we're good. The consequence of this is that the invalidate methods on the analysis manager which operate over many passes now consume their PreservedAnalyses object, update it to "preserve" every analysis pass to which it delivers an invalidation (regardless of whether the pass chooses to be removed, or handles the invalidation itself by updating itself). Then we return this augmented set from the invalidate routine, letting the pass manager take the result and use the intersection of *that* across each pass run to compute the final preserved set. This accounts for all the places where the early invalidation of an analysis has already "preserved" it for a future run. I've beefed up the testing and adjusted the assertions to show that we no longer repeatedly invalidate or compute the analyses across nested pass managers. llvm-svn: 225333
2015-01-07 02:58:35 +01:00
; RUN: -passes='require<no-op-module>,module(require<no-op-module>,cgscc(require<no-op-cgscc>,function(require<no-op-function>,invalidate<all>,require<no-op-function>),require<no-op-cgscc>),require<no-op-module>),require<no-op-module>' %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-INVALIDATE-ALL-CG
; CHECK-INVALIDATE-ALL-CG: Starting llvm::Module pass manager run
; CHECK-INVALIDATE-ALL-CG: Running pass: RequireAnalysisPass
; CHECK-INVALIDATE-ALL-CG: Running analysis: NoOpModuleAnalysis
; CHECK-INVALIDATE-ALL-CG: Starting llvm::Module pass manager run
; CHECK-INVALIDATE-ALL-CG: Running pass: RequireAnalysisPass
; CHECK-INVALIDATE-ALL-CG-NOT: Running analysis: NoOpModuleAnalysis
[PM] Introduce basic update capabilities to the new PM's CGSCC pass manager, including both plumbing and logic to handle function pass updates. There are three fundamentally tied changes here: 1) Plumbing *some* mechanism for updating the CGSCC pass manager as the CG changes while passes are running. 2) Changing the CGSCC pass manager infrastructure to have support for the underlying graph to mutate mid-pass run. 3) Actually updating the CG after function passes run. I can separate them if necessary, but I think its really useful to have them together as the needs of #3 drove #2, and that in turn drove #1. The plumbing technique is to extend the "run" method signature with extra arguments. We provide the call graph that intrinsically is available as it is the basis of the pass manager's IR units, and an output parameter that records the results of updating the call graph during an SCC passes's run. Note that "...UpdateResult" isn't a *great* name here... suggestions very welcome. I tried a pretty frustrating number of different data structures and such for the innards of the update result. Every other one failed for one reason or another. Sometimes I just couldn't keep the layers of complexity right in my head. The thing that really worked was to just directly provide access to the underlying structures used to walk the call graph so that their updates could be informed by the *particular* nature of the change to the graph. The technique for how to make the pass management infrastructure cope with mutating graphs was also something that took a really, really large number of iterations to get to a place where I was happy. Here are some of the considerations that drove the design: - We operate at three levels within the infrastructure: RefSCC, SCC, and Node. In each case, we are working bottom up and so we want to continue to iterate on the "lowest" node as the graph changes. Look at how we iterate over nodes in an SCC running function passes as those function passes mutate the CG. We continue to iterate on the "lowest" SCC, which is the one that continues to contain the function just processed. - The call graph structure re-uses SCCs (and RefSCCs) during mutation events for the *highest* entry in the resulting new subgraph, not the lowest. This means that it is necessary to continually update the current SCC or RefSCC as it shifts. This is really surprising and subtle, and took a long time for me to work out. I actually tried changing the call graph to provide the opposite behavior, and it breaks *EVERYTHING*. The graph update algorithms are really deeply tied to this particualr pattern. - When SCCs or RefSCCs are split apart and refined and we continually re-pin our processing to the bottom one in the subgraph, we need to enqueue the newly formed SCCs and RefSCCs for subsequent processing. Queuing them presents a few challenges: 1) SCCs and RefSCCs use wildly different iteration strategies at a high level. We end up needing to converge them on worklist approaches that can be extended in order to be able to handle the mutations. 2) The order of the enqueuing need to remain bottom-up post-order so that we don't get surprising order of visitation for things like the inliner. 3) We need the worklists to have set semantics so we don't duplicate things endlessly. We don't need a *persistent* set though because we always keep processing the bottom node!!!! This is super, super surprising to me and took a long time to convince myself this is correct, but I'm pretty sure it is... Once we sink down to the bottom node, we can't re-split out the same node in any way, and the postorder of the current queue is fixed and unchanging. 4) We need to make sure that the "current" SCC or RefSCC actually gets enqueued here such that we re-visit it because we continue processing a *new*, *bottom* SCC/RefSCC. - We also need the ability to *skip* SCCs and RefSCCs that get merged into a larger component. We even need the ability to skip *nodes* from an SCC that are no longer part of that SCC. This led to the design you see in the patch which uses SetVector-based worklists. The RefSCC worklist is always empty until an update occurs and is just used to handle those RefSCCs created by updates as the others don't even exist yet and are formed on-demand during the bottom-up walk. The SCC worklist is pre-populated from the RefSCC, and we push new SCCs onto it and blacklist existing SCCs on it to get the desired processing. We then *directly* update these when updating the call graph as I was never able to find a satisfactory abstraction around the update strategy. Finally, we need to compute the updates for function passes. This is mostly used as an initial customer of all the update mechanisms to drive their design to at least cover some real set of use cases. There are a bunch of interesting things that came out of doing this: - It is really nice to do this a function at a time because that function is likely hot in the cache. This means we want even the function pass adaptor to support online updates to the call graph! - To update the call graph after arbitrary function pass mutations is quite hard. We have to build a fairly comprehensive set of data structures and then process them. Fortunately, some of this code is related to the code for building the cal graph in the first place. Unfortunately, very little of it makes any sense to share because the nature of what we're doing is so very different. I've factored out the one part that made sense at least. - We need to transfer these updates into the various structures for the CGSCC pass manager. Once those were more sanely worked out, this became relatively easier. But some of those needs necessitated changes to the LazyCallGraph interface to make it significantly easier to extract the changed SCCs from an update operation. - We also need to update the CGSCC analysis manager as the shape of the graph changes. When an SCC is merged away we need to clear analyses associated with it from the analysis manager which we didn't have support for in the analysis manager infrsatructure. New SCCs are easy! But then we have the case that the original SCC has its shape changed but remains in the call graph. There we need to *invalidate* the analyses associated with it. - We also need to invalidate analyses after we *finish* processing an SCC. But the analyses we need to invalidate here are *only those for the newly updated SCC*!!! Because we only continue processing the bottom SCC, if we split SCCs apart the original one gets invalidated once when its shape changes and is not processed farther so its analyses will be correct. It is the bottom SCC which continues being processed and needs to have the "normal" invalidation done based on the preserved analyses set. All of this is mostly background and context for the changes here. Many thanks to all the reviewers who helped here. Especially Sanjoy who caught several interesting bugs in the graph algorithms, David, Sean, and others who all helped with feedback. Differential Revision: http://reviews.llvm.org/D21464 llvm-svn: 279618
2016-08-24 11:37:14 +02:00
; CHECK-INVALIDATE-ALL-CG: Starting CGSCC pass manager run
; CHECK-INVALIDATE-ALL-CG: Running pass: RequireAnalysisPass
; CHECK-INVALIDATE-ALL-CG: Running analysis: NoOpCGSCCAnalysis
; CHECK-INVALIDATE-ALL-CG: Starting llvm::Function pass manager run
; CHECK-INVALIDATE-ALL-CG: Running pass: RequireAnalysisPass
; CHECK-INVALIDATE-ALL-CG: Running analysis: NoOpFunctionAnalysis
; CHECK-INVALIDATE-ALL-CG: Running pass: InvalidateAllAnalysesPass
; CHECK-INVALIDATE-ALL-CG: Invalidating analysis: NoOpFunctionAnalysis
; CHECK-INVALIDATE-ALL-CG: Running pass: RequireAnalysisPass
; CHECK-INVALIDATE-ALL-CG: Running analysis: NoOpFunctionAnalysis
; CHECK-INVALIDATE-ALL-CG: Finished llvm::Function pass manager run
; CHECK-INVALIDATE-ALL-CG-NOT: Running analysis: NoOpFunctionAnalysis
; CHECK-INVALIDATE-ALL-CG: Invalidating analysis: NoOpCGSCCAnalysis
; CHECK-INVALIDATE-ALL-CG: Running pass: RequireAnalysisPass
; CHECK-INVALIDATE-ALL-CG: Running analysis: NoOpCGSCCAnalysis
[PM] Introduce basic update capabilities to the new PM's CGSCC pass manager, including both plumbing and logic to handle function pass updates. There are three fundamentally tied changes here: 1) Plumbing *some* mechanism for updating the CGSCC pass manager as the CG changes while passes are running. 2) Changing the CGSCC pass manager infrastructure to have support for the underlying graph to mutate mid-pass run. 3) Actually updating the CG after function passes run. I can separate them if necessary, but I think its really useful to have them together as the needs of #3 drove #2, and that in turn drove #1. The plumbing technique is to extend the "run" method signature with extra arguments. We provide the call graph that intrinsically is available as it is the basis of the pass manager's IR units, and an output parameter that records the results of updating the call graph during an SCC passes's run. Note that "...UpdateResult" isn't a *great* name here... suggestions very welcome. I tried a pretty frustrating number of different data structures and such for the innards of the update result. Every other one failed for one reason or another. Sometimes I just couldn't keep the layers of complexity right in my head. The thing that really worked was to just directly provide access to the underlying structures used to walk the call graph so that their updates could be informed by the *particular* nature of the change to the graph. The technique for how to make the pass management infrastructure cope with mutating graphs was also something that took a really, really large number of iterations to get to a place where I was happy. Here are some of the considerations that drove the design: - We operate at three levels within the infrastructure: RefSCC, SCC, and Node. In each case, we are working bottom up and so we want to continue to iterate on the "lowest" node as the graph changes. Look at how we iterate over nodes in an SCC running function passes as those function passes mutate the CG. We continue to iterate on the "lowest" SCC, which is the one that continues to contain the function just processed. - The call graph structure re-uses SCCs (and RefSCCs) during mutation events for the *highest* entry in the resulting new subgraph, not the lowest. This means that it is necessary to continually update the current SCC or RefSCC as it shifts. This is really surprising and subtle, and took a long time for me to work out. I actually tried changing the call graph to provide the opposite behavior, and it breaks *EVERYTHING*. The graph update algorithms are really deeply tied to this particualr pattern. - When SCCs or RefSCCs are split apart and refined and we continually re-pin our processing to the bottom one in the subgraph, we need to enqueue the newly formed SCCs and RefSCCs for subsequent processing. Queuing them presents a few challenges: 1) SCCs and RefSCCs use wildly different iteration strategies at a high level. We end up needing to converge them on worklist approaches that can be extended in order to be able to handle the mutations. 2) The order of the enqueuing need to remain bottom-up post-order so that we don't get surprising order of visitation for things like the inliner. 3) We need the worklists to have set semantics so we don't duplicate things endlessly. We don't need a *persistent* set though because we always keep processing the bottom node!!!! This is super, super surprising to me and took a long time to convince myself this is correct, but I'm pretty sure it is... Once we sink down to the bottom node, we can't re-split out the same node in any way, and the postorder of the current queue is fixed and unchanging. 4) We need to make sure that the "current" SCC or RefSCC actually gets enqueued here such that we re-visit it because we continue processing a *new*, *bottom* SCC/RefSCC. - We also need the ability to *skip* SCCs and RefSCCs that get merged into a larger component. We even need the ability to skip *nodes* from an SCC that are no longer part of that SCC. This led to the design you see in the patch which uses SetVector-based worklists. The RefSCC worklist is always empty until an update occurs and is just used to handle those RefSCCs created by updates as the others don't even exist yet and are formed on-demand during the bottom-up walk. The SCC worklist is pre-populated from the RefSCC, and we push new SCCs onto it and blacklist existing SCCs on it to get the desired processing. We then *directly* update these when updating the call graph as I was never able to find a satisfactory abstraction around the update strategy. Finally, we need to compute the updates for function passes. This is mostly used as an initial customer of all the update mechanisms to drive their design to at least cover some real set of use cases. There are a bunch of interesting things that came out of doing this: - It is really nice to do this a function at a time because that function is likely hot in the cache. This means we want even the function pass adaptor to support online updates to the call graph! - To update the call graph after arbitrary function pass mutations is quite hard. We have to build a fairly comprehensive set of data structures and then process them. Fortunately, some of this code is related to the code for building the cal graph in the first place. Unfortunately, very little of it makes any sense to share because the nature of what we're doing is so very different. I've factored out the one part that made sense at least. - We need to transfer these updates into the various structures for the CGSCC pass manager. Once those were more sanely worked out, this became relatively easier. But some of those needs necessitated changes to the LazyCallGraph interface to make it significantly easier to extract the changed SCCs from an update operation. - We also need to update the CGSCC analysis manager as the shape of the graph changes. When an SCC is merged away we need to clear analyses associated with it from the analysis manager which we didn't have support for in the analysis manager infrsatructure. New SCCs are easy! But then we have the case that the original SCC has its shape changed but remains in the call graph. There we need to *invalidate* the analyses associated with it. - We also need to invalidate analyses after we *finish* processing an SCC. But the analyses we need to invalidate here are *only those for the newly updated SCC*!!! Because we only continue processing the bottom SCC, if we split SCCs apart the original one gets invalidated once when its shape changes and is not processed farther so its analyses will be correct. It is the bottom SCC which continues being processed and needs to have the "normal" invalidation done based on the preserved analyses set. All of this is mostly background and context for the changes here. Many thanks to all the reviewers who helped here. Especially Sanjoy who caught several interesting bugs in the graph algorithms, David, Sean, and others who all helped with feedback. Differential Revision: http://reviews.llvm.org/D21464 llvm-svn: 279618
2016-08-24 11:37:14 +02:00
; CHECK-INVALIDATE-ALL-CG: Finished CGSCC pass manager run
; CHECK-INVALIDATE-ALL-CG-NOT: Invalidating analysis: NoOpCGSCCAnalysis
; CHECK-INVALIDATE-ALL-CG: Invalidating analysis: NoOpModuleAnalysis
; CHECK-INVALIDATE-ALL-CG: Running pass: RequireAnalysisPass
; CHECK-INVALIDATE-ALL-CG: Running analysis: NoOpModuleAnalysis
; CHECK-INVALIDATE-ALL-CG: Finished llvm::Module pass manager run
; CHECK-INVALIDATE-ALL-CG-NOT: Invalidating analysis: NoOpModuleAnalysis
; CHECK-INVALIDATE-ALL-CG: Running pass: RequireAnalysisPass
; CHECK-INVALIDATE-ALL-CG-NOT: Running analysis: NoOpModuleAnalysis
; CHECK-INVALIDATE-ALL-CG: Finished llvm::Module pass manager run
; RUN: opt -disable-output -disable-verify -debug-pass-manager %s 2>&1 \
; RUN: -passes='require<targetlibinfo>,invalidate<all>,require<targetlibinfo>' \
; RUN: | FileCheck %s --check-prefix=CHECK-TLI
; CHECK-TLI: Starting llvm::Module pass manager run
; CHECK-TLI: Running pass: RequireAnalysisPass
; CHECK-TLI: Running analysis: TargetLibraryAnalysis
; CHECK-TLI: Running pass: InvalidateAllAnalysesPass
; CHECK-TLI-NOT: Invalidating analysis: TargetLibraryAnalysis
; CHECK-TLI: Running pass: RequireAnalysisPass
; CHECK-TLI-NOT: Running analysis: TargetLibraryAnalysis
; CHECK-TLI: Finished llvm::Module pass manager run
; RUN: opt -disable-output -disable-verify -debug-pass-manager %s 2>&1 \
; RUN: -passes='require<targetir>,invalidate<all>,require<targetir>' \
; RUN: | FileCheck %s --check-prefix=CHECK-TIRA
; CHECK-TIRA: Starting llvm::Module pass manager run
; CHECK-TIRA: Running pass: RequireAnalysisPass
; CHECK-TIRA: Running analysis: TargetIRAnalysis
; CHECK-TIRA: Running pass: InvalidateAllAnalysesPass
; CHECK-TIRA-NOT: Invalidating analysis: TargetIRAnalysis
; CHECK-TIRA: Running pass: RequireAnalysisPass
; CHECK-TIRA-NOT: Running analysis: TargetIRAnalysis
; CHECK-TIRA: Finished llvm::Module pass manager run
; RUN: opt -disable-output -disable-verify -debug-pass-manager %s 2>&1 \
; RUN: -passes='require<domtree>' \
; RUN: | FileCheck %s --check-prefix=CHECK-DT
; CHECK-DT: Starting llvm::Module pass manager run
; CHECK-DT: Running pass: RequireAnalysisPass
; CHECK-DT: Running analysis: DominatorTreeAnalysis
; CHECK-DT: Finished llvm::Module pass manager run
; RUN: opt -disable-output -disable-verify -debug-pass-manager %s 2>&1 \
; RUN: -passes='require<basic-aa>' \
; RUN: | FileCheck %s --check-prefix=CHECK-BASIC-AA
; CHECK-BASIC-AA: Starting llvm::Module pass manager run
; CHECK-BASIC-AA: Running pass: RequireAnalysisPass
; CHECK-BASIC-AA: Running analysis: BasicAA
; CHECK-BASIC-AA: Finished llvm::Module pass manager run
; RUN: opt -disable-output -disable-verify -debug-pass-manager %s 2>&1 \
; RUN: -passes='require<aa>' -aa-pipeline='basic-aa' \
; RUN: | FileCheck %s --check-prefix=CHECK-AA
; CHECK-AA: Starting llvm::Module pass manager run
; CHECK-AA: Running pass: RequireAnalysisPass
; CHECK-AA: Running analysis: AAManager
; CHECK-AA: Running analysis: BasicAA
; CHECK-AA: Finished llvm::Module pass manager run
; RUN: opt -disable-output -disable-verify -debug-pass-manager %s 2>&1 \
; RUN: -passes='require<aa>' -aa-pipeline='default' \
; RUN: | FileCheck %s --check-prefix=CHECK-AA-DEFAULT
; CHECK-AA-DEFAULT: Starting llvm::Module pass manager run
; CHECK-AA-DEFAULT: Running pass: RequireAnalysisPass
; CHECK-AA-DEFAULT: Running analysis: AAManager
; CHECK-AA-DEFAULT: Running analysis: BasicAA
; CHECK-AA-DEFAULT: Running analysis: ScopedNoAliasAA
; CHECK-AA-DEFAULT: Running analysis: TypeBasedAA
; CHECK-AA-DEFAULT: Finished llvm::Module pass manager run
; RUN: opt -disable-output -disable-verify -debug-pass-manager %s 2>&1 \
; RUN: -passes='require<aa>,invalidate<domtree>,aa-eval' -aa-pipeline='basic-aa' \
; RUN: | FileCheck %s --check-prefix=CHECK-AA-FUNCTION-INVALIDATE
; CHECK-AA-FUNCTION-INVALIDATE: Starting llvm::Function pass manager run
; CHECK-AA-FUNCTION-INVALIDATE: Running pass: RequireAnalysisPass
; CHECK-AA-FUNCTION-INVALIDATE: Running analysis: AAManager
; CHECK-AA-FUNCTION-INVALIDATE: Running analysis: BasicAA
; CHECK-AA-FUNCTION-INVALIDATE: Running pass: InvalidateAnalysisPass
; CHECK-AA-FUNCTION-INVALIDATE: Invalidating analysis: DominatorTreeAnalysis
; CHECK-AA-FUNCTION-INVALIDATE: Invalidating analysis: BasicAA
; CHECK-AA-FUNCTION-INVALIDATE: Invalidating analysis: AAManager
; CHECK-AA-FUNCTION-INVALIDATE: Running pass: AAEvaluator
; CHECK-AA-FUNCTION-INVALIDATE: Running analysis: AAManager
; CHECK-AA-FUNCTION-INVALIDATE: Running analysis: BasicAA
; CHECK-AA-FUNCTION-INVALIDATE: Finished llvm::Function pass manager run
; RUN: opt -disable-output -disable-verify -debug-pass-manager %s 2>&1 \
; RUN: -passes='require<globals-aa>,function(require<aa>),invalidate<globals-aa>,require<globals-aa>,function(aa-eval)' -aa-pipeline='globals-aa' \
; RUN: | FileCheck %s --check-prefix=CHECK-AA-MODULE-INVALIDATE
; CHECK-AA-MODULE-INVALIDATE: Starting llvm::Module pass manager run
; CHECK-AA-MODULE-INVALIDATE: Running pass: RequireAnalysisPass
; CHECK-AA-MODULE-INVALIDATE: Running analysis: GlobalsAA
; CHECK-AA-MODULE-INVALIDATE: Starting llvm::Function pass manager run
; CHECK-AA-MODULE-INVALIDATE: Running pass: RequireAnalysisPass
; CHECK-AA-MODULE-INVALIDATE: Running analysis: AAManager
; CHECK-AA-MODULE-INVALIDATE: Finished llvm::Function pass manager run
; CHECK-AA-MODULE-INVALIDATE: Running pass: InvalidateAnalysisPass
; CHECK-AA-MODULE-INVALIDATE: Invalidating analysis: AAManager
; CHECK-AA-MODULE-INVALIDATE: Invalidating analysis: GlobalsAA
; CHECK-AA-MODULE-INVALIDATE: Running pass: RequireAnalysisPass
; CHECK-AA-MODULE-INVALIDATE: Running analysis: GlobalsAA
; CHECK-AA-MODULE-INVALIDATE: Starting llvm::Function pass manager run
; CHECK-AA-MODULE-INVALIDATE: Running pass: AAEvaluator
; CHECK-AA-MODULE-INVALIDATE: Running analysis: AAManager
; CHECK-AA-MODULE-INVALIDATE: Finished llvm::Function pass manager run
; CHECK-AA-MODULE-INVALIDATE: Finished llvm::Module pass manager run
; RUN: opt -disable-output -disable-verify -debug-pass-manager %s 2>&1 \
; RUN: -passes='require<memdep>' \
; RUN: | FileCheck %s --check-prefix=CHECK-MEMDEP
; CHECK-MEMDEP: Starting llvm::Module pass manager run
; CHECK-MEMDEP: Running pass: RequireAnalysisPass
; CHECK-MEMDEP: Running analysis: MemoryDependenceAnalysis
; CHECK-MEMDEP: Finished llvm::Module pass manager run
; RUN: opt -disable-output -disable-verify -debug-pass-manager %s 2>&1 \
; RUN: -passes='require<callgraph>' \
; RUN: | FileCheck %s --check-prefix=CHECK-CALLGRAPH
; CHECK-CALLGRAPH: Starting llvm::Module pass manager run
; CHECK-CALLGRAPH: Running pass: RequireAnalysisPass
; CHECK-CALLGRAPH: Running analysis: CallGraphAnalysis
; CHECK-CALLGRAPH: Finished llvm::Module pass manager run
; RUN: opt -disable-output -disable-verify -debug-pass-manager \
; RUN: -passes='default<O0>' %s 2>&1 \
[PM] Introduce a reasonable port of the main per-module pass pipeline from the old pass manager in the new one. I'm not trying to support (initially) the numerous options that are currently available to customize the pass pipeline. If we end up really wanting them, we can add them later, but I suspect many are no longer interesting. The simplicity of omitting them will help a lot as we sort out what the pipeline should look like in the new PM. I've also documented to the best of my ability *why* each pass or group of passes is used so that reading the pipeline is more helpful. In many cases I think we have some questionable choices of ordering and I've left FIXME comments in place so we know what to come back and revisit going forward. But for now, I've left it as similar to the current pipeline as I could. Lastly, I've had to comment out several places where passes are not ported to the new pass manager or where the loop pass infrastructure is not yet ready. I did at least fix a few bugs in the loop pass infrastructure uncovered by running the full pipeline, but I didn't want to go too far in this patch -- I'll come back and re-enable these as the infrastructure comes online. But I'd like to keep the comments in place because I don't want to lose track of which passes need to be enabled and where they go. One thing that seemed like a significant API improvement was to require that we don't build pipelines for O0. It seems to have no real benefit. I've also switched back to returning pass managers by value as at this API layer it feels much more natural to me for composition. But if others disagree, I'm happy to go back to an output parameter. I'm not 100% happy with the testing strategy currently, but it seems at least OK. I may come back and try to refactor or otherwise improve this in subsequent patches but I wanted to at least get a good starting point in place. Differential Revision: https://reviews.llvm.org/D28042 llvm-svn: 290325
2016-12-22 07:59:15 +01:00
; RUN: | FileCheck %s --check-prefix=CHECK-O0
; CHECK-O0: Starting llvm::Module pass manager run
; CHECK-O0-NEXT: Finished llvm::Module pass manager run
; RUN: opt -disable-output -disable-verify -debug-pass-manager \
; RUN: -passes='repeat<3>(no-op-module)' %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-REPEAT-MODULE-PASS
; CHECK-REPEAT-MODULE-PASS: Starting llvm::Module pass manager run
; CHECK-REPEAT-MODULE-PASS-NEXT: Running pass: RepeatedPass
; CHECK-REPEAT-MODULE-PASS-NEXT: Starting llvm::Module pass manager run
; CHECK-REPEAT-MODULE-PASS-NEXT: Running pass: NoOpModulePass
; CHECK-REPEAT-MODULE-PASS-NEXT: Finished llvm::Module pass manager run
; CHECK-REPEAT-MODULE-PASS-NEXT: Starting llvm::Module pass manager run
; CHECK-REPEAT-MODULE-PASS-NEXT: Running pass: NoOpModulePass
; CHECK-REPEAT-MODULE-PASS-NEXT: Finished llvm::Module pass manager run
; CHECK-REPEAT-MODULE-PASS-NEXT: Starting llvm::Module pass manager run
; CHECK-REPEAT-MODULE-PASS-NEXT: Running pass: NoOpModulePass
; CHECK-REPEAT-MODULE-PASS-NEXT: Finished llvm::Module pass manager run
; CHECK-REPEAT-MODULE-PASS-NEXT: Finished llvm::Module pass manager run
; RUN: opt -disable-output -disable-verify -debug-pass-manager \
; RUN: -passes='cgscc(repeat<3>(no-op-cgscc))' %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-REPEAT-CGSCC-PASS
; CHECK-REPEAT-CGSCC-PASS: Starting llvm::Module pass manager run
; CHECK-REPEAT-CGSCC-PASS-NEXT: Running pass: ModuleToPostOrderCGSCCPassAdaptor
; CHECK-REPEAT-CGSCC-PASS-NEXT: Running analysis: InnerAnalysisManagerProxy<{{.*(CGSCCAnalysisManager|AnalysisManager<.*LazyCallGraph::SCC.*>).*}},{{.*}}Module>
; CHECK-REPEAT-CGSCC-PASS-NEXT: Running analysis: InnerAnalysisManagerProxy<{{.*(FunctionAnalysisManager|AnalysisManager<.*Function.*>).*}},{{.*}}Module>
; CHECK-REPEAT-CGSCC-PASS-NEXT: Running analysis: LazyCallGraphAnalysis
; CHECK-REPEAT-CGSCC-PASS-NEXT: Running analysis: TargetLibraryAnalysis
[New PM] Introducing PassInstrumentation framework Pass Execution Instrumentation interface enables customizable instrumentation of pass execution, as per "RFC: Pass Execution Instrumentation interface" posted 06/07/2018 on llvm-dev@ The intent is to provide a common machinery to implement all the pass-execution-debugging features like print-before/after, opt-bisect, time-passes etc. Here we get a basic implementation consisting of: * PassInstrumentationCallbacks class that handles registration of callbacks and access to them. * PassInstrumentation class that handles instrumentation-point interfaces that call into PassInstrumentationCallbacks. * Callbacks accept StringRef which is just a name of the Pass right now. There were some ideas to pass an opaque wrapper for the pointer to pass instance, however it appears that pointer does not actually identify the instance (adaptors and managers might have the same address with the pass they govern). Hence it was decided to go simple for now and then later decide on what the proper mental model of identifying a "pass in a phase of pipeline" is. * Callbacks accept llvm::Any serving as a wrapper for const IRUnit*, to remove direct dependencies on different IRUnits (e.g. Analyses). * PassInstrumentationAnalysis analysis is explicitly requested from PassManager through usual AnalysisManager::getResult. All pass managers were updated to run that to get PassInstrumentation object for instrumentation calls. * Using tuples/index_sequence getAnalysisResult helper to extract generic AnalysisManager's extra args out of a generic PassManager's extra args. This is the only way I was able to explicitly run getResult for PassInstrumentationAnalysis out of a generic code like PassManager::run or RepeatedPass::run. TODO: Upon lengthy discussions we agreed to accept this as an initial implementation and then get rid of getAnalysisResult by improving RepeatedPass implementation. * PassBuilder takes PassInstrumentationCallbacks object to pass it further into PassInstrumentationAnalysis. Callbacks registration should be performed directly through PassInstrumentationCallbacks. * new-pm tests updated to account for PassInstrumentationAnalysis being run * Added PassInstrumentation tests to PassBuilderCallbacks unit tests. Other unit tests updated with registration of the now-required PassInstrumentationAnalysis. Made getName helper to return std::string (instead of StringRef initially) to fix asan builtbot failures on CGSCC tests. Reviewers: chandlerc, philip.pfaffe Differential Revision: https://reviews.llvm.org/D47858 llvm-svn: 342664
2018-09-20 19:08:45 +02:00
; CHECK-REPEAT-CGSCC-PASS-NEXT: Running analysis: PassInstrumentationAnalysis
[PM] Introduce basic update capabilities to the new PM's CGSCC pass manager, including both plumbing and logic to handle function pass updates. There are three fundamentally tied changes here: 1) Plumbing *some* mechanism for updating the CGSCC pass manager as the CG changes while passes are running. 2) Changing the CGSCC pass manager infrastructure to have support for the underlying graph to mutate mid-pass run. 3) Actually updating the CG after function passes run. I can separate them if necessary, but I think its really useful to have them together as the needs of #3 drove #2, and that in turn drove #1. The plumbing technique is to extend the "run" method signature with extra arguments. We provide the call graph that intrinsically is available as it is the basis of the pass manager's IR units, and an output parameter that records the results of updating the call graph during an SCC passes's run. Note that "...UpdateResult" isn't a *great* name here... suggestions very welcome. I tried a pretty frustrating number of different data structures and such for the innards of the update result. Every other one failed for one reason or another. Sometimes I just couldn't keep the layers of complexity right in my head. The thing that really worked was to just directly provide access to the underlying structures used to walk the call graph so that their updates could be informed by the *particular* nature of the change to the graph. The technique for how to make the pass management infrastructure cope with mutating graphs was also something that took a really, really large number of iterations to get to a place where I was happy. Here are some of the considerations that drove the design: - We operate at three levels within the infrastructure: RefSCC, SCC, and Node. In each case, we are working bottom up and so we want to continue to iterate on the "lowest" node as the graph changes. Look at how we iterate over nodes in an SCC running function passes as those function passes mutate the CG. We continue to iterate on the "lowest" SCC, which is the one that continues to contain the function just processed. - The call graph structure re-uses SCCs (and RefSCCs) during mutation events for the *highest* entry in the resulting new subgraph, not the lowest. This means that it is necessary to continually update the current SCC or RefSCC as it shifts. This is really surprising and subtle, and took a long time for me to work out. I actually tried changing the call graph to provide the opposite behavior, and it breaks *EVERYTHING*. The graph update algorithms are really deeply tied to this particualr pattern. - When SCCs or RefSCCs are split apart and refined and we continually re-pin our processing to the bottom one in the subgraph, we need to enqueue the newly formed SCCs and RefSCCs for subsequent processing. Queuing them presents a few challenges: 1) SCCs and RefSCCs use wildly different iteration strategies at a high level. We end up needing to converge them on worklist approaches that can be extended in order to be able to handle the mutations. 2) The order of the enqueuing need to remain bottom-up post-order so that we don't get surprising order of visitation for things like the inliner. 3) We need the worklists to have set semantics so we don't duplicate things endlessly. We don't need a *persistent* set though because we always keep processing the bottom node!!!! This is super, super surprising to me and took a long time to convince myself this is correct, but I'm pretty sure it is... Once we sink down to the bottom node, we can't re-split out the same node in any way, and the postorder of the current queue is fixed and unchanging. 4) We need to make sure that the "current" SCC or RefSCC actually gets enqueued here such that we re-visit it because we continue processing a *new*, *bottom* SCC/RefSCC. - We also need the ability to *skip* SCCs and RefSCCs that get merged into a larger component. We even need the ability to skip *nodes* from an SCC that are no longer part of that SCC. This led to the design you see in the patch which uses SetVector-based worklists. The RefSCC worklist is always empty until an update occurs and is just used to handle those RefSCCs created by updates as the others don't even exist yet and are formed on-demand during the bottom-up walk. The SCC worklist is pre-populated from the RefSCC, and we push new SCCs onto it and blacklist existing SCCs on it to get the desired processing. We then *directly* update these when updating the call graph as I was never able to find a satisfactory abstraction around the update strategy. Finally, we need to compute the updates for function passes. This is mostly used as an initial customer of all the update mechanisms to drive their design to at least cover some real set of use cases. There are a bunch of interesting things that came out of doing this: - It is really nice to do this a function at a time because that function is likely hot in the cache. This means we want even the function pass adaptor to support online updates to the call graph! - To update the call graph after arbitrary function pass mutations is quite hard. We have to build a fairly comprehensive set of data structures and then process them. Fortunately, some of this code is related to the code for building the cal graph in the first place. Unfortunately, very little of it makes any sense to share because the nature of what we're doing is so very different. I've factored out the one part that made sense at least. - We need to transfer these updates into the various structures for the CGSCC pass manager. Once those were more sanely worked out, this became relatively easier. But some of those needs necessitated changes to the LazyCallGraph interface to make it significantly easier to extract the changed SCCs from an update operation. - We also need to update the CGSCC analysis manager as the shape of the graph changes. When an SCC is merged away we need to clear analyses associated with it from the analysis manager which we didn't have support for in the analysis manager infrsatructure. New SCCs are easy! But then we have the case that the original SCC has its shape changed but remains in the call graph. There we need to *invalidate* the analyses associated with it. - We also need to invalidate analyses after we *finish* processing an SCC. But the analyses we need to invalidate here are *only those for the newly updated SCC*!!! Because we only continue processing the bottom SCC, if we split SCCs apart the original one gets invalidated once when its shape changes and is not processed farther so its analyses will be correct. It is the bottom SCC which continues being processed and needs to have the "normal" invalidation done based on the preserved analyses set. All of this is mostly background and context for the changes here. Many thanks to all the reviewers who helped here. Especially Sanjoy who caught several interesting bugs in the graph algorithms, David, Sean, and others who all helped with feedback. Differential Revision: http://reviews.llvm.org/D21464 llvm-svn: 279618
2016-08-24 11:37:14 +02:00
; CHECK-REPEAT-CGSCC-PASS-NEXT: Starting CGSCC pass manager run
; CHECK-REPEAT-CGSCC-PASS-NEXT: Running pass: RepeatedPass
[PM] Introduce basic update capabilities to the new PM's CGSCC pass manager, including both plumbing and logic to handle function pass updates. There are three fundamentally tied changes here: 1) Plumbing *some* mechanism for updating the CGSCC pass manager as the CG changes while passes are running. 2) Changing the CGSCC pass manager infrastructure to have support for the underlying graph to mutate mid-pass run. 3) Actually updating the CG after function passes run. I can separate them if necessary, but I think its really useful to have them together as the needs of #3 drove #2, and that in turn drove #1. The plumbing technique is to extend the "run" method signature with extra arguments. We provide the call graph that intrinsically is available as it is the basis of the pass manager's IR units, and an output parameter that records the results of updating the call graph during an SCC passes's run. Note that "...UpdateResult" isn't a *great* name here... suggestions very welcome. I tried a pretty frustrating number of different data structures and such for the innards of the update result. Every other one failed for one reason or another. Sometimes I just couldn't keep the layers of complexity right in my head. The thing that really worked was to just directly provide access to the underlying structures used to walk the call graph so that their updates could be informed by the *particular* nature of the change to the graph. The technique for how to make the pass management infrastructure cope with mutating graphs was also something that took a really, really large number of iterations to get to a place where I was happy. Here are some of the considerations that drove the design: - We operate at three levels within the infrastructure: RefSCC, SCC, and Node. In each case, we are working bottom up and so we want to continue to iterate on the "lowest" node as the graph changes. Look at how we iterate over nodes in an SCC running function passes as those function passes mutate the CG. We continue to iterate on the "lowest" SCC, which is the one that continues to contain the function just processed. - The call graph structure re-uses SCCs (and RefSCCs) during mutation events for the *highest* entry in the resulting new subgraph, not the lowest. This means that it is necessary to continually update the current SCC or RefSCC as it shifts. This is really surprising and subtle, and took a long time for me to work out. I actually tried changing the call graph to provide the opposite behavior, and it breaks *EVERYTHING*. The graph update algorithms are really deeply tied to this particualr pattern. - When SCCs or RefSCCs are split apart and refined and we continually re-pin our processing to the bottom one in the subgraph, we need to enqueue the newly formed SCCs and RefSCCs for subsequent processing. Queuing them presents a few challenges: 1) SCCs and RefSCCs use wildly different iteration strategies at a high level. We end up needing to converge them on worklist approaches that can be extended in order to be able to handle the mutations. 2) The order of the enqueuing need to remain bottom-up post-order so that we don't get surprising order of visitation for things like the inliner. 3) We need the worklists to have set semantics so we don't duplicate things endlessly. We don't need a *persistent* set though because we always keep processing the bottom node!!!! This is super, super surprising to me and took a long time to convince myself this is correct, but I'm pretty sure it is... Once we sink down to the bottom node, we can't re-split out the same node in any way, and the postorder of the current queue is fixed and unchanging. 4) We need to make sure that the "current" SCC or RefSCC actually gets enqueued here such that we re-visit it because we continue processing a *new*, *bottom* SCC/RefSCC. - We also need the ability to *skip* SCCs and RefSCCs that get merged into a larger component. We even need the ability to skip *nodes* from an SCC that are no longer part of that SCC. This led to the design you see in the patch which uses SetVector-based worklists. The RefSCC worklist is always empty until an update occurs and is just used to handle those RefSCCs created by updates as the others don't even exist yet and are formed on-demand during the bottom-up walk. The SCC worklist is pre-populated from the RefSCC, and we push new SCCs onto it and blacklist existing SCCs on it to get the desired processing. We then *directly* update these when updating the call graph as I was never able to find a satisfactory abstraction around the update strategy. Finally, we need to compute the updates for function passes. This is mostly used as an initial customer of all the update mechanisms to drive their design to at least cover some real set of use cases. There are a bunch of interesting things that came out of doing this: - It is really nice to do this a function at a time because that function is likely hot in the cache. This means we want even the function pass adaptor to support online updates to the call graph! - To update the call graph after arbitrary function pass mutations is quite hard. We have to build a fairly comprehensive set of data structures and then process them. Fortunately, some of this code is related to the code for building the cal graph in the first place. Unfortunately, very little of it makes any sense to share because the nature of what we're doing is so very different. I've factored out the one part that made sense at least. - We need to transfer these updates into the various structures for the CGSCC pass manager. Once those were more sanely worked out, this became relatively easier. But some of those needs necessitated changes to the LazyCallGraph interface to make it significantly easier to extract the changed SCCs from an update operation. - We also need to update the CGSCC analysis manager as the shape of the graph changes. When an SCC is merged away we need to clear analyses associated with it from the analysis manager which we didn't have support for in the analysis manager infrsatructure. New SCCs are easy! But then we have the case that the original SCC has its shape changed but remains in the call graph. There we need to *invalidate* the analyses associated with it. - We also need to invalidate analyses after we *finish* processing an SCC. But the analyses we need to invalidate here are *only those for the newly updated SCC*!!! Because we only continue processing the bottom SCC, if we split SCCs apart the original one gets invalidated once when its shape changes and is not processed farther so its analyses will be correct. It is the bottom SCC which continues being processed and needs to have the "normal" invalidation done based on the preserved analyses set. All of this is mostly background and context for the changes here. Many thanks to all the reviewers who helped here. Especially Sanjoy who caught several interesting bugs in the graph algorithms, David, Sean, and others who all helped with feedback. Differential Revision: http://reviews.llvm.org/D21464 llvm-svn: 279618
2016-08-24 11:37:14 +02:00
; CHECK-REPEAT-CGSCC-PASS-NEXT: Starting CGSCC pass manager run
; CHECK-REPEAT-CGSCC-PASS-NEXT: Running pass: NoOpCGSCCPass
[PM] Introduce basic update capabilities to the new PM's CGSCC pass manager, including both plumbing and logic to handle function pass updates. There are three fundamentally tied changes here: 1) Plumbing *some* mechanism for updating the CGSCC pass manager as the CG changes while passes are running. 2) Changing the CGSCC pass manager infrastructure to have support for the underlying graph to mutate mid-pass run. 3) Actually updating the CG after function passes run. I can separate them if necessary, but I think its really useful to have them together as the needs of #3 drove #2, and that in turn drove #1. The plumbing technique is to extend the "run" method signature with extra arguments. We provide the call graph that intrinsically is available as it is the basis of the pass manager's IR units, and an output parameter that records the results of updating the call graph during an SCC passes's run. Note that "...UpdateResult" isn't a *great* name here... suggestions very welcome. I tried a pretty frustrating number of different data structures and such for the innards of the update result. Every other one failed for one reason or another. Sometimes I just couldn't keep the layers of complexity right in my head. The thing that really worked was to just directly provide access to the underlying structures used to walk the call graph so that their updates could be informed by the *particular* nature of the change to the graph. The technique for how to make the pass management infrastructure cope with mutating graphs was also something that took a really, really large number of iterations to get to a place where I was happy. Here are some of the considerations that drove the design: - We operate at three levels within the infrastructure: RefSCC, SCC, and Node. In each case, we are working bottom up and so we want to continue to iterate on the "lowest" node as the graph changes. Look at how we iterate over nodes in an SCC running function passes as those function passes mutate the CG. We continue to iterate on the "lowest" SCC, which is the one that continues to contain the function just processed. - The call graph structure re-uses SCCs (and RefSCCs) during mutation events for the *highest* entry in the resulting new subgraph, not the lowest. This means that it is necessary to continually update the current SCC or RefSCC as it shifts. This is really surprising and subtle, and took a long time for me to work out. I actually tried changing the call graph to provide the opposite behavior, and it breaks *EVERYTHING*. The graph update algorithms are really deeply tied to this particualr pattern. - When SCCs or RefSCCs are split apart and refined and we continually re-pin our processing to the bottom one in the subgraph, we need to enqueue the newly formed SCCs and RefSCCs for subsequent processing. Queuing them presents a few challenges: 1) SCCs and RefSCCs use wildly different iteration strategies at a high level. We end up needing to converge them on worklist approaches that can be extended in order to be able to handle the mutations. 2) The order of the enqueuing need to remain bottom-up post-order so that we don't get surprising order of visitation for things like the inliner. 3) We need the worklists to have set semantics so we don't duplicate things endlessly. We don't need a *persistent* set though because we always keep processing the bottom node!!!! This is super, super surprising to me and took a long time to convince myself this is correct, but I'm pretty sure it is... Once we sink down to the bottom node, we can't re-split out the same node in any way, and the postorder of the current queue is fixed and unchanging. 4) We need to make sure that the "current" SCC or RefSCC actually gets enqueued here such that we re-visit it because we continue processing a *new*, *bottom* SCC/RefSCC. - We also need the ability to *skip* SCCs and RefSCCs that get merged into a larger component. We even need the ability to skip *nodes* from an SCC that are no longer part of that SCC. This led to the design you see in the patch which uses SetVector-based worklists. The RefSCC worklist is always empty until an update occurs and is just used to handle those RefSCCs created by updates as the others don't even exist yet and are formed on-demand during the bottom-up walk. The SCC worklist is pre-populated from the RefSCC, and we push new SCCs onto it and blacklist existing SCCs on it to get the desired processing. We then *directly* update these when updating the call graph as I was never able to find a satisfactory abstraction around the update strategy. Finally, we need to compute the updates for function passes. This is mostly used as an initial customer of all the update mechanisms to drive their design to at least cover some real set of use cases. There are a bunch of interesting things that came out of doing this: - It is really nice to do this a function at a time because that function is likely hot in the cache. This means we want even the function pass adaptor to support online updates to the call graph! - To update the call graph after arbitrary function pass mutations is quite hard. We have to build a fairly comprehensive set of data structures and then process them. Fortunately, some of this code is related to the code for building the cal graph in the first place. Unfortunately, very little of it makes any sense to share because the nature of what we're doing is so very different. I've factored out the one part that made sense at least. - We need to transfer these updates into the various structures for the CGSCC pass manager. Once those were more sanely worked out, this became relatively easier. But some of those needs necessitated changes to the LazyCallGraph interface to make it significantly easier to extract the changed SCCs from an update operation. - We also need to update the CGSCC analysis manager as the shape of the graph changes. When an SCC is merged away we need to clear analyses associated with it from the analysis manager which we didn't have support for in the analysis manager infrsatructure. New SCCs are easy! But then we have the case that the original SCC has its shape changed but remains in the call graph. There we need to *invalidate* the analyses associated with it. - We also need to invalidate analyses after we *finish* processing an SCC. But the analyses we need to invalidate here are *only those for the newly updated SCC*!!! Because we only continue processing the bottom SCC, if we split SCCs apart the original one gets invalidated once when its shape changes and is not processed farther so its analyses will be correct. It is the bottom SCC which continues being processed and needs to have the "normal" invalidation done based on the preserved analyses set. All of this is mostly background and context for the changes here. Many thanks to all the reviewers who helped here. Especially Sanjoy who caught several interesting bugs in the graph algorithms, David, Sean, and others who all helped with feedback. Differential Revision: http://reviews.llvm.org/D21464 llvm-svn: 279618
2016-08-24 11:37:14 +02:00
; CHECK-REPEAT-CGSCC-PASS-NEXT: Finished CGSCC pass manager run
; CHECK-REPEAT-CGSCC-PASS-NEXT: Starting CGSCC pass manager run
; CHECK-REPEAT-CGSCC-PASS-NEXT: Running pass: NoOpCGSCCPass
[PM] Introduce basic update capabilities to the new PM's CGSCC pass manager, including both plumbing and logic to handle function pass updates. There are three fundamentally tied changes here: 1) Plumbing *some* mechanism for updating the CGSCC pass manager as the CG changes while passes are running. 2) Changing the CGSCC pass manager infrastructure to have support for the underlying graph to mutate mid-pass run. 3) Actually updating the CG after function passes run. I can separate them if necessary, but I think its really useful to have them together as the needs of #3 drove #2, and that in turn drove #1. The plumbing technique is to extend the "run" method signature with extra arguments. We provide the call graph that intrinsically is available as it is the basis of the pass manager's IR units, and an output parameter that records the results of updating the call graph during an SCC passes's run. Note that "...UpdateResult" isn't a *great* name here... suggestions very welcome. I tried a pretty frustrating number of different data structures and such for the innards of the update result. Every other one failed for one reason or another. Sometimes I just couldn't keep the layers of complexity right in my head. The thing that really worked was to just directly provide access to the underlying structures used to walk the call graph so that their updates could be informed by the *particular* nature of the change to the graph. The technique for how to make the pass management infrastructure cope with mutating graphs was also something that took a really, really large number of iterations to get to a place where I was happy. Here are some of the considerations that drove the design: - We operate at three levels within the infrastructure: RefSCC, SCC, and Node. In each case, we are working bottom up and so we want to continue to iterate on the "lowest" node as the graph changes. Look at how we iterate over nodes in an SCC running function passes as those function passes mutate the CG. We continue to iterate on the "lowest" SCC, which is the one that continues to contain the function just processed. - The call graph structure re-uses SCCs (and RefSCCs) during mutation events for the *highest* entry in the resulting new subgraph, not the lowest. This means that it is necessary to continually update the current SCC or RefSCC as it shifts. This is really surprising and subtle, and took a long time for me to work out. I actually tried changing the call graph to provide the opposite behavior, and it breaks *EVERYTHING*. The graph update algorithms are really deeply tied to this particualr pattern. - When SCCs or RefSCCs are split apart and refined and we continually re-pin our processing to the bottom one in the subgraph, we need to enqueue the newly formed SCCs and RefSCCs for subsequent processing. Queuing them presents a few challenges: 1) SCCs and RefSCCs use wildly different iteration strategies at a high level. We end up needing to converge them on worklist approaches that can be extended in order to be able to handle the mutations. 2) The order of the enqueuing need to remain bottom-up post-order so that we don't get surprising order of visitation for things like the inliner. 3) We need the worklists to have set semantics so we don't duplicate things endlessly. We don't need a *persistent* set though because we always keep processing the bottom node!!!! This is super, super surprising to me and took a long time to convince myself this is correct, but I'm pretty sure it is... Once we sink down to the bottom node, we can't re-split out the same node in any way, and the postorder of the current queue is fixed and unchanging. 4) We need to make sure that the "current" SCC or RefSCC actually gets enqueued here such that we re-visit it because we continue processing a *new*, *bottom* SCC/RefSCC. - We also need the ability to *skip* SCCs and RefSCCs that get merged into a larger component. We even need the ability to skip *nodes* from an SCC that are no longer part of that SCC. This led to the design you see in the patch which uses SetVector-based worklists. The RefSCC worklist is always empty until an update occurs and is just used to handle those RefSCCs created by updates as the others don't even exist yet and are formed on-demand during the bottom-up walk. The SCC worklist is pre-populated from the RefSCC, and we push new SCCs onto it and blacklist existing SCCs on it to get the desired processing. We then *directly* update these when updating the call graph as I was never able to find a satisfactory abstraction around the update strategy. Finally, we need to compute the updates for function passes. This is mostly used as an initial customer of all the update mechanisms to drive their design to at least cover some real set of use cases. There are a bunch of interesting things that came out of doing this: - It is really nice to do this a function at a time because that function is likely hot in the cache. This means we want even the function pass adaptor to support online updates to the call graph! - To update the call graph after arbitrary function pass mutations is quite hard. We have to build a fairly comprehensive set of data structures and then process them. Fortunately, some of this code is related to the code for building the cal graph in the first place. Unfortunately, very little of it makes any sense to share because the nature of what we're doing is so very different. I've factored out the one part that made sense at least. - We need to transfer these updates into the various structures for the CGSCC pass manager. Once those were more sanely worked out, this became relatively easier. But some of those needs necessitated changes to the LazyCallGraph interface to make it significantly easier to extract the changed SCCs from an update operation. - We also need to update the CGSCC analysis manager as the shape of the graph changes. When an SCC is merged away we need to clear analyses associated with it from the analysis manager which we didn't have support for in the analysis manager infrsatructure. New SCCs are easy! But then we have the case that the original SCC has its shape changed but remains in the call graph. There we need to *invalidate* the analyses associated with it. - We also need to invalidate analyses after we *finish* processing an SCC. But the analyses we need to invalidate here are *only those for the newly updated SCC*!!! Because we only continue processing the bottom SCC, if we split SCCs apart the original one gets invalidated once when its shape changes and is not processed farther so its analyses will be correct. It is the bottom SCC which continues being processed and needs to have the "normal" invalidation done based on the preserved analyses set. All of this is mostly background and context for the changes here. Many thanks to all the reviewers who helped here. Especially Sanjoy who caught several interesting bugs in the graph algorithms, David, Sean, and others who all helped with feedback. Differential Revision: http://reviews.llvm.org/D21464 llvm-svn: 279618
2016-08-24 11:37:14 +02:00
; CHECK-REPEAT-CGSCC-PASS-NEXT: Finished CGSCC pass manager run
; CHECK-REPEAT-CGSCC-PASS-NEXT: Starting CGSCC pass manager run
; CHECK-REPEAT-CGSCC-PASS-NEXT: Running pass: NoOpCGSCCPass
[PM] Introduce basic update capabilities to the new PM's CGSCC pass manager, including both plumbing and logic to handle function pass updates. There are three fundamentally tied changes here: 1) Plumbing *some* mechanism for updating the CGSCC pass manager as the CG changes while passes are running. 2) Changing the CGSCC pass manager infrastructure to have support for the underlying graph to mutate mid-pass run. 3) Actually updating the CG after function passes run. I can separate them if necessary, but I think its really useful to have them together as the needs of #3 drove #2, and that in turn drove #1. The plumbing technique is to extend the "run" method signature with extra arguments. We provide the call graph that intrinsically is available as it is the basis of the pass manager's IR units, and an output parameter that records the results of updating the call graph during an SCC passes's run. Note that "...UpdateResult" isn't a *great* name here... suggestions very welcome. I tried a pretty frustrating number of different data structures and such for the innards of the update result. Every other one failed for one reason or another. Sometimes I just couldn't keep the layers of complexity right in my head. The thing that really worked was to just directly provide access to the underlying structures used to walk the call graph so that their updates could be informed by the *particular* nature of the change to the graph. The technique for how to make the pass management infrastructure cope with mutating graphs was also something that took a really, really large number of iterations to get to a place where I was happy. Here are some of the considerations that drove the design: - We operate at three levels within the infrastructure: RefSCC, SCC, and Node. In each case, we are working bottom up and so we want to continue to iterate on the "lowest" node as the graph changes. Look at how we iterate over nodes in an SCC running function passes as those function passes mutate the CG. We continue to iterate on the "lowest" SCC, which is the one that continues to contain the function just processed. - The call graph structure re-uses SCCs (and RefSCCs) during mutation events for the *highest* entry in the resulting new subgraph, not the lowest. This means that it is necessary to continually update the current SCC or RefSCC as it shifts. This is really surprising and subtle, and took a long time for me to work out. I actually tried changing the call graph to provide the opposite behavior, and it breaks *EVERYTHING*. The graph update algorithms are really deeply tied to this particualr pattern. - When SCCs or RefSCCs are split apart and refined and we continually re-pin our processing to the bottom one in the subgraph, we need to enqueue the newly formed SCCs and RefSCCs for subsequent processing. Queuing them presents a few challenges: 1) SCCs and RefSCCs use wildly different iteration strategies at a high level. We end up needing to converge them on worklist approaches that can be extended in order to be able to handle the mutations. 2) The order of the enqueuing need to remain bottom-up post-order so that we don't get surprising order of visitation for things like the inliner. 3) We need the worklists to have set semantics so we don't duplicate things endlessly. We don't need a *persistent* set though because we always keep processing the bottom node!!!! This is super, super surprising to me and took a long time to convince myself this is correct, but I'm pretty sure it is... Once we sink down to the bottom node, we can't re-split out the same node in any way, and the postorder of the current queue is fixed and unchanging. 4) We need to make sure that the "current" SCC or RefSCC actually gets enqueued here such that we re-visit it because we continue processing a *new*, *bottom* SCC/RefSCC. - We also need the ability to *skip* SCCs and RefSCCs that get merged into a larger component. We even need the ability to skip *nodes* from an SCC that are no longer part of that SCC. This led to the design you see in the patch which uses SetVector-based worklists. The RefSCC worklist is always empty until an update occurs and is just used to handle those RefSCCs created by updates as the others don't even exist yet and are formed on-demand during the bottom-up walk. The SCC worklist is pre-populated from the RefSCC, and we push new SCCs onto it and blacklist existing SCCs on it to get the desired processing. We then *directly* update these when updating the call graph as I was never able to find a satisfactory abstraction around the update strategy. Finally, we need to compute the updates for function passes. This is mostly used as an initial customer of all the update mechanisms to drive their design to at least cover some real set of use cases. There are a bunch of interesting things that came out of doing this: - It is really nice to do this a function at a time because that function is likely hot in the cache. This means we want even the function pass adaptor to support online updates to the call graph! - To update the call graph after arbitrary function pass mutations is quite hard. We have to build a fairly comprehensive set of data structures and then process them. Fortunately, some of this code is related to the code for building the cal graph in the first place. Unfortunately, very little of it makes any sense to share because the nature of what we're doing is so very different. I've factored out the one part that made sense at least. - We need to transfer these updates into the various structures for the CGSCC pass manager. Once those were more sanely worked out, this became relatively easier. But some of those needs necessitated changes to the LazyCallGraph interface to make it significantly easier to extract the changed SCCs from an update operation. - We also need to update the CGSCC analysis manager as the shape of the graph changes. When an SCC is merged away we need to clear analyses associated with it from the analysis manager which we didn't have support for in the analysis manager infrsatructure. New SCCs are easy! But then we have the case that the original SCC has its shape changed but remains in the call graph. There we need to *invalidate* the analyses associated with it. - We also need to invalidate analyses after we *finish* processing an SCC. But the analyses we need to invalidate here are *only those for the newly updated SCC*!!! Because we only continue processing the bottom SCC, if we split SCCs apart the original one gets invalidated once when its shape changes and is not processed farther so its analyses will be correct. It is the bottom SCC which continues being processed and needs to have the "normal" invalidation done based on the preserved analyses set. All of this is mostly background and context for the changes here. Many thanks to all the reviewers who helped here. Especially Sanjoy who caught several interesting bugs in the graph algorithms, David, Sean, and others who all helped with feedback. Differential Revision: http://reviews.llvm.org/D21464 llvm-svn: 279618
2016-08-24 11:37:14 +02:00
; CHECK-REPEAT-CGSCC-PASS-NEXT: Finished CGSCC pass manager run
; CHECK-REPEAT-CGSCC-PASS-NEXT: Finished CGSCC pass manager run
; CHECK-REPEAT-CGSCC-PASS-NEXT: Finished llvm::Module pass manager run
; RUN: opt -disable-output -disable-verify -debug-pass-manager \
; RUN: -passes='function(repeat<3>(no-op-function))' %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-REPEAT-FUNCTION-PASS
; CHECK-REPEAT-FUNCTION-PASS: Starting llvm::Module pass manager run
; CHECK-REPEAT-FUNCTION-PASS-NEXT: Running pass: ModuleToFunctionPassAdaptor
; CHECK-REPEAT-FUNCTION-PASS-NEXT: Running analysis: InnerAnalysisManagerProxy<{{.*}}>
[New PM] Introducing PassInstrumentation framework Pass Execution Instrumentation interface enables customizable instrumentation of pass execution, as per "RFC: Pass Execution Instrumentation interface" posted 06/07/2018 on llvm-dev@ The intent is to provide a common machinery to implement all the pass-execution-debugging features like print-before/after, opt-bisect, time-passes etc. Here we get a basic implementation consisting of: * PassInstrumentationCallbacks class that handles registration of callbacks and access to them. * PassInstrumentation class that handles instrumentation-point interfaces that call into PassInstrumentationCallbacks. * Callbacks accept StringRef which is just a name of the Pass right now. There were some ideas to pass an opaque wrapper for the pointer to pass instance, however it appears that pointer does not actually identify the instance (adaptors and managers might have the same address with the pass they govern). Hence it was decided to go simple for now and then later decide on what the proper mental model of identifying a "pass in a phase of pipeline" is. * Callbacks accept llvm::Any serving as a wrapper for const IRUnit*, to remove direct dependencies on different IRUnits (e.g. Analyses). * PassInstrumentationAnalysis analysis is explicitly requested from PassManager through usual AnalysisManager::getResult. All pass managers were updated to run that to get PassInstrumentation object for instrumentation calls. * Using tuples/index_sequence getAnalysisResult helper to extract generic AnalysisManager's extra args out of a generic PassManager's extra args. This is the only way I was able to explicitly run getResult for PassInstrumentationAnalysis out of a generic code like PassManager::run or RepeatedPass::run. TODO: Upon lengthy discussions we agreed to accept this as an initial implementation and then get rid of getAnalysisResult by improving RepeatedPass implementation. * PassBuilder takes PassInstrumentationCallbacks object to pass it further into PassInstrumentationAnalysis. Callbacks registration should be performed directly through PassInstrumentationCallbacks. * new-pm tests updated to account for PassInstrumentationAnalysis being run * Added PassInstrumentation tests to PassBuilderCallbacks unit tests. Other unit tests updated with registration of the now-required PassInstrumentationAnalysis. Made getName helper to return std::string (instead of StringRef initially) to fix asan builtbot failures on CGSCC tests. Reviewers: chandlerc, philip.pfaffe Differential Revision: https://reviews.llvm.org/D47858 llvm-svn: 342664
2018-09-20 19:08:45 +02:00
; CHECK-REPEAT-FUNCTION-PASS-NEXT: Running analysis: PassInstrumentationAnalysis
; CHECK-REPEAT-FUNCTION-PASS-NEXT: Starting llvm::Function pass manager run
; CHECK-REPEAT-FUNCTION-PASS-NEXT: Running pass: RepeatedPass
; CHECK-REPEAT-FUNCTION-PASS-NEXT: Starting llvm::Function pass manager run
; CHECK-REPEAT-FUNCTION-PASS-NEXT: Running pass: NoOpFunctionPass
; CHECK-REPEAT-FUNCTION-PASS-NEXT: Finished llvm::Function pass manager run
; CHECK-REPEAT-FUNCTION-PASS-NEXT: Starting llvm::Function pass manager run
; CHECK-REPEAT-FUNCTION-PASS-NEXT: Running pass: NoOpFunctionPass
; CHECK-REPEAT-FUNCTION-PASS-NEXT: Finished llvm::Function pass manager run
; CHECK-REPEAT-FUNCTION-PASS-NEXT: Starting llvm::Function pass manager run
; CHECK-REPEAT-FUNCTION-PASS-NEXT: Running pass: NoOpFunctionPass
; CHECK-REPEAT-FUNCTION-PASS-NEXT: Finished llvm::Function pass manager run
; CHECK-REPEAT-FUNCTION-PASS-NEXT: Finished llvm::Function pass manager run
; CHECK-REPEAT-FUNCTION-PASS-NEXT: Finished llvm::Module pass manager run
; RUN: opt -disable-output -disable-verify -debug-pass-manager \
; RUN: -passes='loop(repeat<3>(no-op-loop))' %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-REPEAT-LOOP-PASS
; CHECK-REPEAT-LOOP-PASS: Starting llvm::Module pass manager run
; CHECK-REPEAT-LOOP-PASS-NEXT: Running pass: ModuleToFunctionPassAdaptor
; CHECK-REPEAT-LOOP-PASS-NEXT: Running analysis: InnerAnalysisManagerProxy<{{.*}}>
[New PM] Introducing PassInstrumentation framework Pass Execution Instrumentation interface enables customizable instrumentation of pass execution, as per "RFC: Pass Execution Instrumentation interface" posted 06/07/2018 on llvm-dev@ The intent is to provide a common machinery to implement all the pass-execution-debugging features like print-before/after, opt-bisect, time-passes etc. Here we get a basic implementation consisting of: * PassInstrumentationCallbacks class that handles registration of callbacks and access to them. * PassInstrumentation class that handles instrumentation-point interfaces that call into PassInstrumentationCallbacks. * Callbacks accept StringRef which is just a name of the Pass right now. There were some ideas to pass an opaque wrapper for the pointer to pass instance, however it appears that pointer does not actually identify the instance (adaptors and managers might have the same address with the pass they govern). Hence it was decided to go simple for now and then later decide on what the proper mental model of identifying a "pass in a phase of pipeline" is. * Callbacks accept llvm::Any serving as a wrapper for const IRUnit*, to remove direct dependencies on different IRUnits (e.g. Analyses). * PassInstrumentationAnalysis analysis is explicitly requested from PassManager through usual AnalysisManager::getResult. All pass managers were updated to run that to get PassInstrumentation object for instrumentation calls. * Using tuples/index_sequence getAnalysisResult helper to extract generic AnalysisManager's extra args out of a generic PassManager's extra args. This is the only way I was able to explicitly run getResult for PassInstrumentationAnalysis out of a generic code like PassManager::run or RepeatedPass::run. TODO: Upon lengthy discussions we agreed to accept this as an initial implementation and then get rid of getAnalysisResult by improving RepeatedPass implementation. * PassBuilder takes PassInstrumentationCallbacks object to pass it further into PassInstrumentationAnalysis. Callbacks registration should be performed directly through PassInstrumentationCallbacks. * new-pm tests updated to account for PassInstrumentationAnalysis being run * Added PassInstrumentation tests to PassBuilderCallbacks unit tests. Other unit tests updated with registration of the now-required PassInstrumentationAnalysis. Made getName helper to return std::string (instead of StringRef initially) to fix asan builtbot failures on CGSCC tests. Reviewers: chandlerc, philip.pfaffe Differential Revision: https://reviews.llvm.org/D47858 llvm-svn: 342664
2018-09-20 19:08:45 +02:00
; CHECK-REPEAT-LOOP-PASS-NEXT: Running analysis: PassInstrumentationAnalysis
; CHECK-REPEAT-LOOP-PASS-NEXT: Starting llvm::Function pass manager run
; CHECK-REPEAT-LOOP-PASS-NEXT: Running pass: FunctionToLoopPassAdaptor
; CHECK-REPEAT-LOOP-PASS-NEXT: Starting llvm::Function pass manager run
; CHECK-REPEAT-LOOP-PASS-NEXT: Running pass: LoopSimplify
; CHECK-REPEAT-LOOP-PASS-NEXT: Running analysis: LoopAnalysis
; CHECK-REPEAT-LOOP-PASS-NEXT: Running analysis: DominatorTreeAnalysis
; CHECK-REPEAT-LOOP-PASS-NEXT: Running analysis: AssumptionAnalysis
; CHECK-REPEAT-LOOP-PASS-NEXT: Invalidating all non-preserved analyses
; CHECK-REPEAT-LOOP-PASS-NEXT: Running pass: LCSSAPass
; CHECK-REPEAT-LOOP-PASS-NEXT: Finished llvm::Function pass manager run
[PM] Introduce a reasonable port of the main per-module pass pipeline from the old pass manager in the new one. I'm not trying to support (initially) the numerous options that are currently available to customize the pass pipeline. If we end up really wanting them, we can add them later, but I suspect many are no longer interesting. The simplicity of omitting them will help a lot as we sort out what the pipeline should look like in the new PM. I've also documented to the best of my ability *why* each pass or group of passes is used so that reading the pipeline is more helpful. In many cases I think we have some questionable choices of ordering and I've left FIXME comments in place so we know what to come back and revisit going forward. But for now, I've left it as similar to the current pipeline as I could. Lastly, I've had to comment out several places where passes are not ported to the new pass manager or where the loop pass infrastructure is not yet ready. I did at least fix a few bugs in the loop pass infrastructure uncovered by running the full pipeline, but I didn't want to go too far in this patch -- I'll come back and re-enable these as the infrastructure comes online. But I'd like to keep the comments in place because I don't want to lose track of which passes need to be enabled and where they go. One thing that seemed like a significant API improvement was to require that we don't build pipelines for O0. It seems to have no real benefit. I've also switched back to returning pass managers by value as at this API layer it feels much more natural to me for composition. But if others disagree, I'm happy to go back to an output parameter. I'm not 100% happy with the testing strategy currently, but it seems at least OK. I may come back and try to refactor or otherwise improve this in subsequent patches but I wanted to at least get a good starting point in place. Differential Revision: https://reviews.llvm.org/D28042 llvm-svn: 290325
2016-12-22 07:59:15 +01:00
; CHECK-REPEAT-LOOP-PASS-NEXT: Running analysis: AAManager
; CHECK-REPEAT-LOOP-PASS-NEXT: Running analysis: TargetLibraryAnalysis
[PM] Rewrite the loop pass manager to use a worklist and augmented run arguments much like the CGSCC pass manager. This is a major redesign following the pattern establish for the CGSCC layer to support updates to the set of loops during the traversal of the loop nest and to support invalidation of analyses. An additional significant burden in the loop PM is that so many passes require access to a large number of function analyses. Manually ensuring these are cached, available, and preserved has been a long-standing burden in LLVM even with the help of the automatic scheduling in the old pass manager. And it made the new pass manager extremely unweildy. With this design, we can package the common analyses up while in a function pass and make them immediately available to all the loop passes. While in some cases this is unnecessary, I think the simplicity afforded is worth it. This does not (yet) address loop simplified form or LCSSA form, but those are the next things on my radar and I have a clear plan for them. While the patch is very large, most of it is either mechanically updating loop passes to the new API or the new testing for the loop PM. The code for it is reasonably compact. I have not yet updated all of the loop passes to correctly leverage the update mechanisms demonstrated in the unittests. I'll do that in follow-up patches along with improved FileCheck tests for those passes that ensure things work in more realistic scenarios. In many cases, there isn't much we can do with these until the loop simplified form and LCSSA form are in place. Differential Revision: https://reviews.llvm.org/D28292 llvm-svn: 291651
2017-01-11 07:23:21 +01:00
; CHECK-REPEAT-LOOP-PASS-NEXT: Running analysis: ScalarEvolutionAnalysis
; CHECK-REPEAT-LOOP-PASS-NEXT: Running analysis: TargetIRAnalysis
; CHECK-REPEAT-LOOP-PASS-NEXT: Running analysis: InnerAnalysisManagerProxy<{{.*}}>
[PM] Rewrite the loop pass manager to use a worklist and augmented run arguments much like the CGSCC pass manager. This is a major redesign following the pattern establish for the CGSCC layer to support updates to the set of loops during the traversal of the loop nest and to support invalidation of analyses. An additional significant burden in the loop PM is that so many passes require access to a large number of function analyses. Manually ensuring these are cached, available, and preserved has been a long-standing burden in LLVM even with the help of the automatic scheduling in the old pass manager. And it made the new pass manager extremely unweildy. With this design, we can package the common analyses up while in a function pass and make them immediately available to all the loop passes. While in some cases this is unnecessary, I think the simplicity afforded is worth it. This does not (yet) address loop simplified form or LCSSA form, but those are the next things on my radar and I have a clear plan for them. While the patch is very large, most of it is either mechanically updating loop passes to the new API or the new testing for the loop PM. The code for it is reasonably compact. I have not yet updated all of the loop passes to correctly leverage the update mechanisms demonstrated in the unittests. I'll do that in follow-up patches along with improved FileCheck tests for those passes that ensure things work in more realistic scenarios. In many cases, there isn't much we can do with these until the loop simplified form and LCSSA form are in place. Differential Revision: https://reviews.llvm.org/D28292 llvm-svn: 291651
2017-01-11 07:23:21 +01:00
; CHECK-REPEAT-LOOP-PASS-NEXT: Starting Loop pass manager run
[New PM] Introducing PassInstrumentation framework Pass Execution Instrumentation interface enables customizable instrumentation of pass execution, as per "RFC: Pass Execution Instrumentation interface" posted 06/07/2018 on llvm-dev@ The intent is to provide a common machinery to implement all the pass-execution-debugging features like print-before/after, opt-bisect, time-passes etc. Here we get a basic implementation consisting of: * PassInstrumentationCallbacks class that handles registration of callbacks and access to them. * PassInstrumentation class that handles instrumentation-point interfaces that call into PassInstrumentationCallbacks. * Callbacks accept StringRef which is just a name of the Pass right now. There were some ideas to pass an opaque wrapper for the pointer to pass instance, however it appears that pointer does not actually identify the instance (adaptors and managers might have the same address with the pass they govern). Hence it was decided to go simple for now and then later decide on what the proper mental model of identifying a "pass in a phase of pipeline" is. * Callbacks accept llvm::Any serving as a wrapper for const IRUnit*, to remove direct dependencies on different IRUnits (e.g. Analyses). * PassInstrumentationAnalysis analysis is explicitly requested from PassManager through usual AnalysisManager::getResult. All pass managers were updated to run that to get PassInstrumentation object for instrumentation calls. * Using tuples/index_sequence getAnalysisResult helper to extract generic AnalysisManager's extra args out of a generic PassManager's extra args. This is the only way I was able to explicitly run getResult for PassInstrumentationAnalysis out of a generic code like PassManager::run or RepeatedPass::run. TODO: Upon lengthy discussions we agreed to accept this as an initial implementation and then get rid of getAnalysisResult by improving RepeatedPass implementation. * PassBuilder takes PassInstrumentationCallbacks object to pass it further into PassInstrumentationAnalysis. Callbacks registration should be performed directly through PassInstrumentationCallbacks. * new-pm tests updated to account for PassInstrumentationAnalysis being run * Added PassInstrumentation tests to PassBuilderCallbacks unit tests. Other unit tests updated with registration of the now-required PassInstrumentationAnalysis. Made getName helper to return std::string (instead of StringRef initially) to fix asan builtbot failures on CGSCC tests. Reviewers: chandlerc, philip.pfaffe Differential Revision: https://reviews.llvm.org/D47858 llvm-svn: 342664
2018-09-20 19:08:45 +02:00
; CHECK-REPEAT-LOOP-PASS-NEXT: Running analysis: PassInstrumentationAnalysis
; CHECK-REPEAT-LOOP-PASS-NEXT: Running pass: RepeatedPass
[PM] Rewrite the loop pass manager to use a worklist and augmented run arguments much like the CGSCC pass manager. This is a major redesign following the pattern establish for the CGSCC layer to support updates to the set of loops during the traversal of the loop nest and to support invalidation of analyses. An additional significant burden in the loop PM is that so many passes require access to a large number of function analyses. Manually ensuring these are cached, available, and preserved has been a long-standing burden in LLVM even with the help of the automatic scheduling in the old pass manager. And it made the new pass manager extremely unweildy. With this design, we can package the common analyses up while in a function pass and make them immediately available to all the loop passes. While in some cases this is unnecessary, I think the simplicity afforded is worth it. This does not (yet) address loop simplified form or LCSSA form, but those are the next things on my radar and I have a clear plan for them. While the patch is very large, most of it is either mechanically updating loop passes to the new API or the new testing for the loop PM. The code for it is reasonably compact. I have not yet updated all of the loop passes to correctly leverage the update mechanisms demonstrated in the unittests. I'll do that in follow-up patches along with improved FileCheck tests for those passes that ensure things work in more realistic scenarios. In many cases, there isn't much we can do with these until the loop simplified form and LCSSA form are in place. Differential Revision: https://reviews.llvm.org/D28292 llvm-svn: 291651
2017-01-11 07:23:21 +01:00
; CHECK-REPEAT-LOOP-PASS-NEXT: Starting Loop pass manager run
; CHECK-REPEAT-LOOP-PASS-NEXT: Running pass: NoOpLoopPass
[PM] Rewrite the loop pass manager to use a worklist and augmented run arguments much like the CGSCC pass manager. This is a major redesign following the pattern establish for the CGSCC layer to support updates to the set of loops during the traversal of the loop nest and to support invalidation of analyses. An additional significant burden in the loop PM is that so many passes require access to a large number of function analyses. Manually ensuring these are cached, available, and preserved has been a long-standing burden in LLVM even with the help of the automatic scheduling in the old pass manager. And it made the new pass manager extremely unweildy. With this design, we can package the common analyses up while in a function pass and make them immediately available to all the loop passes. While in some cases this is unnecessary, I think the simplicity afforded is worth it. This does not (yet) address loop simplified form or LCSSA form, but those are the next things on my radar and I have a clear plan for them. While the patch is very large, most of it is either mechanically updating loop passes to the new API or the new testing for the loop PM. The code for it is reasonably compact. I have not yet updated all of the loop passes to correctly leverage the update mechanisms demonstrated in the unittests. I'll do that in follow-up patches along with improved FileCheck tests for those passes that ensure things work in more realistic scenarios. In many cases, there isn't much we can do with these until the loop simplified form and LCSSA form are in place. Differential Revision: https://reviews.llvm.org/D28292 llvm-svn: 291651
2017-01-11 07:23:21 +01:00
; CHECK-REPEAT-LOOP-PASS-NEXT: Finished Loop pass manager run
; CHECK-REPEAT-LOOP-PASS-NEXT: Starting Loop pass manager run
; CHECK-REPEAT-LOOP-PASS-NEXT: Running pass: NoOpLoopPass
[PM] Rewrite the loop pass manager to use a worklist and augmented run arguments much like the CGSCC pass manager. This is a major redesign following the pattern establish for the CGSCC layer to support updates to the set of loops during the traversal of the loop nest and to support invalidation of analyses. An additional significant burden in the loop PM is that so many passes require access to a large number of function analyses. Manually ensuring these are cached, available, and preserved has been a long-standing burden in LLVM even with the help of the automatic scheduling in the old pass manager. And it made the new pass manager extremely unweildy. With this design, we can package the common analyses up while in a function pass and make them immediately available to all the loop passes. While in some cases this is unnecessary, I think the simplicity afforded is worth it. This does not (yet) address loop simplified form or LCSSA form, but those are the next things on my radar and I have a clear plan for them. While the patch is very large, most of it is either mechanically updating loop passes to the new API or the new testing for the loop PM. The code for it is reasonably compact. I have not yet updated all of the loop passes to correctly leverage the update mechanisms demonstrated in the unittests. I'll do that in follow-up patches along with improved FileCheck tests for those passes that ensure things work in more realistic scenarios. In many cases, there isn't much we can do with these until the loop simplified form and LCSSA form are in place. Differential Revision: https://reviews.llvm.org/D28292 llvm-svn: 291651
2017-01-11 07:23:21 +01:00
; CHECK-REPEAT-LOOP-PASS-NEXT: Finished Loop pass manager run
; CHECK-REPEAT-LOOP-PASS-NEXT: Starting Loop pass manager run
; CHECK-REPEAT-LOOP-PASS-NEXT: Running pass: NoOpLoopPass
[PM] Rewrite the loop pass manager to use a worklist and augmented run arguments much like the CGSCC pass manager. This is a major redesign following the pattern establish for the CGSCC layer to support updates to the set of loops during the traversal of the loop nest and to support invalidation of analyses. An additional significant burden in the loop PM is that so many passes require access to a large number of function analyses. Manually ensuring these are cached, available, and preserved has been a long-standing burden in LLVM even with the help of the automatic scheduling in the old pass manager. And it made the new pass manager extremely unweildy. With this design, we can package the common analyses up while in a function pass and make them immediately available to all the loop passes. While in some cases this is unnecessary, I think the simplicity afforded is worth it. This does not (yet) address loop simplified form or LCSSA form, but those are the next things on my radar and I have a clear plan for them. While the patch is very large, most of it is either mechanically updating loop passes to the new API or the new testing for the loop PM. The code for it is reasonably compact. I have not yet updated all of the loop passes to correctly leverage the update mechanisms demonstrated in the unittests. I'll do that in follow-up patches along with improved FileCheck tests for those passes that ensure things work in more realistic scenarios. In many cases, there isn't much we can do with these until the loop simplified form and LCSSA form are in place. Differential Revision: https://reviews.llvm.org/D28292 llvm-svn: 291651
2017-01-11 07:23:21 +01:00
; CHECK-REPEAT-LOOP-PASS-NEXT: Finished Loop pass manager run
; CHECK-REPEAT-LOOP-PASS-NEXT: Finished Loop pass manager run
; CHECK-REPEAT-LOOP-PASS-NEXT: Finished llvm::Function pass manager run
; CHECK-REPEAT-LOOP-PASS-NEXT: Invalidating all non-preserved analyses
; CHECK-REPEAT-LOOP-PASS-NEXT: Finished llvm::Module pass manager run
define void @foo(i1 %x, i8* %p1, i8* %p2) {
entry:
store i8 42, i8* %p1
br i1 %x, label %loop, label %exit
loop:
%tmp1 = load i8, i8* %p2
br label %loop
exit:
ret void
}
declare void @bar()