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llvm-mirror/lib/Analysis
Igor Laevsky 747370b198 Strip metadata when speculatively hoisting instructions
This is fix for PR24059.

When we are hoisting instruction above some condition it may turn out
that metadata on this instruction was control dependant on the condition.
This metadata becomes invalid and we need to drop it.

This patch should cover most obvious places of speculative execution (which
I have found by greping isSafeToSpeculativelyExecute). I think there are more
cases but at least this change covers the severe ones.

Differential Revision: http://reviews.llvm.org/D14398

llvm-svn: 252604
2015-11-10 14:10:31 +00:00
..
AliasAnalysis.cpp [AA] Enhance the new AliasAnalysis infrastructure with an optional 2015-10-21 12:15:19 +00:00
AliasAnalysisEvaluator.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
AliasSetTracker.cpp Revert "r251451 - [AliasSetTracker] Use mod/ref information for UnknownInstr" 2015-10-28 22:13:41 +00:00
Analysis.cpp [PM/AA] Rebuild LLVM's alias analysis infrastructure in a way compatible 2015-09-09 17:55:00 +00:00
AssumptionCache.cpp
BasicAliasAnalysis.cpp Refactor: Simplify boolean conditional return statements in llvm/lib/Analysis 2015-11-05 21:07:12 +00:00
BlockFrequencyInfo.cpp Recommit r250345, it was reverted in r250366 to investigate a bot failure. 2015-10-15 14:59:40 +00:00
BlockFrequencyInfoImpl.cpp Recommit r250345, it was reverted in r250366 to investigate a bot failure. 2015-10-15 14:59:40 +00:00
BranchProbabilityInfo.cpp Check the case that the numerator and denominator are both zeros when getting edge probabilities in BPI and return 100% in this case. 2015-10-26 18:00:17 +00:00
CallGraph.cpp [PM/AA] Remove the last relics of the separate IPA library from LLVM, 2015-08-18 17:51:53 +00:00
CallGraphSCCPass.cpp [PM/AA] Remove the last relics of the separate IPA library from LLVM, 2015-08-18 17:51:53 +00:00
CallPrinter.cpp [PM/AA] Remove the last relics of the separate IPA library from LLVM, 2015-08-18 17:51:53 +00:00
CaptureTracking.cpp Refactor: Simplify boolean conditional return statements in llvm/lib/Analysis 2015-11-05 21:07:12 +00:00
CFG.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
CFGPrinter.cpp
CFLAliasAnalysis.cpp [PM/AA] Rebuild LLVM's alias analysis infrastructure in a way compatible 2015-09-09 17:55:00 +00:00
CGSCCPassManager.cpp
CMakeLists.txt [PM/AA] Rebuild LLVM's alias analysis infrastructure in a way compatible 2015-09-09 17:55:00 +00:00
CodeMetrics.cpp Use all_of to simplify control flow. NFC. 2015-10-24 19:30:37 +00:00
ConstantFolding.cpp Enable constant propagation for more math functions 2015-08-27 19:56:57 +00:00
CostModel.cpp Refactor: Simplify boolean conditional return statements in llvm/lib/Analysis 2015-11-05 21:07:12 +00:00
Delinearization.cpp SCEV: Allow simple AddRec * Parameter products in delinearization 2015-10-12 08:02:00 +00:00
DemandedBits.cpp Compute demanded bits for icmp instructions 2015-10-08 12:40:06 +00:00
DependenceAnalysis.cpp [SCEV] Introduce ScalarEvolution::getOne and getZero. 2015-09-23 01:59:04 +00:00
DivergenceAnalysis.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
DominanceFrontier.cpp
DomPrinter.cpp
GlobalsModRef.cpp [GlobalsAA] An indirect global that is initialized is not fair game 2015-10-28 10:41:29 +00:00
InlineCost.cpp Inliner: Do zero-cost inlines even if above a negative threshold (PR24851) 2015-11-10 09:47:48 +00:00
InstCount.cpp
InstructionSimplify.cpp [ValueTracking] Add parameters to isImpliedCondition; NFC 2015-11-06 19:01:08 +00:00
Interval.cpp
IntervalPartition.cpp
IteratedDominanceFrontier.cpp
IVUsers.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
LazyCallGraph.cpp
LazyValueInfo.cpp [LVI] Update a comment to clarify what's actually happening and why 2015-11-04 01:47:04 +00:00
LibCallSemantics.cpp [WinEH] Recognize CoreCLR personality function 2015-10-06 20:28:16 +00:00
Lint.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
LLVMBuild.txt [PM/AA] Remove the last relics of the separate IPA library from LLVM, 2015-08-18 17:51:53 +00:00
Loads.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
LoopAccessAnalysis.cpp Fix LoopAccessAnalysis when potentially nullptr check are involved 2015-11-05 05:49:43 +00:00
LoopInfo.cpp Strip metadata when speculatively hoisting instructions 2015-11-10 14:10:31 +00:00
LoopPass.cpp PM: Rephrase PrintLoopPass as a wrapper around a new-style pass. NFC 2015-11-04 22:24:08 +00:00
Makefile [PM/AA] Remove the last relics of the separate IPA library from LLVM, 2015-08-18 17:51:53 +00:00
MemDepPrinter.cpp [PM/AA] Rebuild LLVM's alias analysis infrastructure in a way compatible 2015-09-09 17:55:00 +00:00
MemDerefPrinter.cpp Take alignment into account in isSafeToSpeculativelyExecute and isSafeToLoadUnconditionally. 2015-08-17 15:54:26 +00:00
MemoryBuiltins.cpp Use find_if to simplify control flow. NFC. 2015-10-24 19:03:15 +00:00
MemoryDependenceAnalysis.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
MemoryLocation.cpp
ModuleDebugInfoPrinter.cpp
ObjCARCAliasAnalysis.cpp [PM/AA] Rebuild LLVM's alias analysis infrastructure in a way compatible 2015-09-09 17:55:00 +00:00
ObjCARCAnalysisUtils.cpp [ARC] Pull the ObjC ARC components that really serve the role of 2015-08-20 08:06:03 +00:00
ObjCARCInstKind.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
OrderedBasicBlock.cpp [CaptureTracker] Provide an ordered basic block to PointerMayBeCapturedBefore 2015-07-31 14:31:35 +00:00
PHITransAddr.cpp [PHITransAddr] Don't assume that instruction operands are translatable 2015-08-09 15:43:02 +00:00
PostDominators.cpp
PtrUseVisitor.cpp
README.txt
RegionInfo.cpp [RegionInfo] Add debug-time region viewer functions 2015-08-10 13:21:59 +00:00
RegionPass.cpp
RegionPrinter.cpp [RegionInfo] Add debug-time region viewer functions 2015-08-10 13:21:59 +00:00
ScalarEvolution.cpp Re-apply r251050 with a for PR25421 2015-11-05 23:45:38 +00:00
ScalarEvolutionAliasAnalysis.cpp [PM/AA] Rebuild LLVM's alias analysis infrastructure in a way compatible 2015-09-09 17:55:00 +00:00
ScalarEvolutionExpander.cpp ADT: Remove last implicit ilist iterator conversions, NFC 2015-11-07 00:01:16 +00:00
ScalarEvolutionNormalization.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
ScopedNoAliasAA.cpp Fix Clang-tidy modernize-use-nullptr warnings in source directories and generated files; other minor cleanups. 2015-10-06 23:24:35 +00:00
SparsePropagation.cpp Analysis: Remove implicit ilist iterator conversions 2015-10-10 00:53:03 +00:00
StratifiedSets.h
TargetLibraryInfo.cpp [TargetLibraryInfo] Add support for fls, flsl, flsll. 2015-11-09 23:23:20 +00:00
TargetTransformInfo.cpp Scalarizer for masked.gather and masked.scatter intrinsics. 2015-10-25 15:37:55 +00:00
Trace.cpp
TypeBasedAliasAnalysis.cpp [PM/AA] Rebuild LLVM's alias analysis infrastructure in a way compatible 2015-09-09 17:55:00 +00:00
ValueTracking.cpp [ValueTracking] Add parameters to isImpliedCondition; NFC 2015-11-06 19:01:08 +00:00
VectorUtils.cpp [LoopVectorize] Address post-commit feedback on r250032 2015-11-09 14:32:05 +00:00

Analysis Opportunities:

//===---------------------------------------------------------------------===//

In test/Transforms/LoopStrengthReduce/quadradic-exit-value.ll, the
ScalarEvolution expression for %r is this:

  {1,+,3,+,2}<loop>

Outside the loop, this could be evaluated simply as (%n * %n), however
ScalarEvolution currently evaluates it as

  (-2 + (2 * (trunc i65 (((zext i64 (-2 + %n) to i65) * (zext i64 (-1 + %n) to i65)) /u 2) to i64)) + (3 * %n))

In addition to being much more complicated, it involves i65 arithmetic,
which is very inefficient when expanded into code.

//===---------------------------------------------------------------------===//

In formatValue in test/CodeGen/X86/lsr-delayed-fold.ll,

ScalarEvolution is forming this expression:

((trunc i64 (-1 * %arg5) to i32) + (trunc i64 %arg5 to i32) + (-1 * (trunc i64 undef to i32)))

This could be folded to

(-1 * (trunc i64 undef to i32))

//===---------------------------------------------------------------------===//