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84 Commits

Author SHA1 Message Date
David Majnemer
9f8ea93cf2 [FunctionAttrs] Don't try to infer returned if it is already on an argument
Trying to infer the 'returned' attribute if an argument is already
'returned' can lead to verification failure: inference might determine
that a different argument is passed through which would result in two
different arguments marked as 'returned'.

This fixes PR30350.

llvm-svn: 281221
2016-09-12 16:04:59 +00:00
David Majnemer
ec0def2c4e Forgot to add a test for r276008.
llvm-svn: 276082
2016-07-20 04:13:05 +00:00
David Majnemer
61cc232b2d [FunctionAttrs] Correct the safety analysis for inference of 'returned'
We skipped over ReturnInsts which didn't return an argument which would
lead us to incorrectly conclude that an argument returned by another
ReturnInst was 'returned'.

This reverts commit r275756.

This fixes PR28610.

llvm-svn: 276008
2016-07-19 18:50:26 +00:00
NAKAMURA Takumi
5d74ab33c6 Revert r275678, "Revert "Revert r275027 - Let FuncAttrs infer the 'returned' argument attribute""
This reverts also r275029, "Update Clang tests after adding inference for the returned argument attribute"

It broke LTO build. Seems miscompilation.

llvm-svn: 275756
2016-07-18 03:23:25 +00:00
Hal Finkel
138dfcb551 Revert "Revert r275027 - Let FuncAttrs infer the 'returned' argument attribute"
This reverts commit r275042; the initial commit triggered self-hosting failures
on ARM/AArch64. James Molloy identified the problematic backend code, which has
been disabled in r275677. Trying again...

Original commit message:

Let FuncAttrs infer the 'returned' argument attribute

A function can have one argument with the 'returned' attribute, indicating that
the associated argument is always the return value of the function. Add
FuncAttrs inference logic.

llvm-svn: 275678
2016-07-16 07:21:28 +00:00
Hal Finkel
3aee15342e Revert r275027 - Let FuncAttrs infer the 'returned' argument attribute
Reverting r275027 and r275033. These seem to cause miscompiles on the AArch64 buildbot.

llvm-svn: 275042
2016-07-11 04:51:23 +00:00
Hal Finkel
6271874a51 Let FuncAttrs infer the 'returned' argument attribute
A function can have one argument with the 'returned' attribute, indicating that
the associated argument is always the return value of the function. Add
FuncAttrs inference logic.

Differential Revision: http://reviews.llvm.org/D22202

llvm-svn: 275027
2016-07-10 22:02:55 +00:00
Justin Bogner
18054ad909 NVPTX: Replace uses of cuda.syncthreads with nvvm.barrier0
Everywhere where cuda.syncthreads or __syncthreads is used, use the
properly namespaced nvvm.barrier0 instead.

llvm-svn: 274664
2016-07-06 20:02:45 +00:00
Sean Silva
145ca3d2aa Remove dead TLI arg of isKnownNonNull and propagate deadness. NFC.
This actually uncovered a surprisingly large chain of ultimately unused
TLI args.
From what I can gather, this argument is a remnant of when
isKnownNonNull would look at the TLI directly.
The current approach seems to be that InferFunctionAttrs runs early in
the pipeline and uses TLI to annotate the TLI-dependent non-null
information as return attributes.

This also removes the dependence of functionattrs on TLI altogether.

llvm-svn: 274455
2016-07-02 23:47:27 +00:00
David Majnemer
cc99e4e75c The absence of noreturn doesn't ensure mayReturn
There are two separate issues:
- LLVM doesn't consider infinite loops to be side effects: we happily
  hoist/sink above/below loops whose bounds are unknown.
- The absence of the noreturn attribute is insufficient for us to know
  if a function will definitely return.  Relying on noreturn in the
  middle-end for any property is an accident waiting to happen.

llvm-svn: 273762
2016-06-25 00:55:12 +00:00
Sean Silva
eb63d26915 [PM] Port ReversePostOrderFunctionAttrs to the new PM
Below are my super rough notes when porting. They can probably serve as
a basic guide for porting other passes to the new PM. As I port more
passes I'll expand and generalize this and make a proper
docs/HowToPortToNewPassManager.rst document. There is also missing
documentation for general concepts and API's in the new PM which will
require some documentation.
Once there is proper documentation in place we can put up a list of
passes that have to be ported and game-ify/crowdsource the rest of the
porting (at least of the middle end; the backend is still unclear).

I will however be taking personal responsibility for ensuring that the
LLD/ELF LTO pipeline is ported in a timely fashion. The remaining passes
to be ported are (do something like
`git grep "<the string in the bullet point below>"` to find the pass):

General Scalar:
[ ] Simplify the CFG
[ ] Jump Threading
[ ] MemCpy Optimization
[ ] Promote Memory to Register
[ ] MergedLoadStoreMotion
[ ] Lazy Value Information Analysis

General IPO:
[ ] Dead Argument Elimination
[ ] Deduce function attributes in RPO

Loop stuff / vectorization stuff:
[ ] Alignment from assumptions
[ ] Canonicalize natural loops
[ ] Delete dead loops
[ ] Loop Access Analysis
[ ] Loop Invariant Code Motion
[ ] Loop Vectorization
[ ] SLP Vectorizer
[ ] Unroll loops

Devirtualization / CFI:
[ ] Cross-DSO CFI
[ ] Whole program devirtualization
[ ] Lower bitset metadata

CGSCC passes:
[ ] Function Integration/Inlining
[ ] Remove unused exception handling info
[ ] Promote 'by reference' arguments to scalars

Please let me know if you are interested in working on any of the passes
in the above list (e.g. reply to the post-commit thread for this patch).
I'll probably be tackling "General Scalar" and "General IPO" first FWIW.

Steps as I port "Deduce function attributes in RPO"
---------------------------------------------------

(note: if you are doing any work based on these notes, please leave a
note in the post-commit review thread for this commit with any
improvements / suggestions / incompleteness you ran into!)

Note: "Deduce function attributes in RPO" is a module pass.

1. Do preparatory refactoring.

Do preparatory factoring. In this case all I had to do was to pull out a static helper (r272503).
(TODO: give more advice here e.g. if pass holds state or something)

2. Rename the old pass class.

llvm/lib/Transforms/IPO/FunctionAttrs.cpp
Rename class ReversePostOrderFunctionAttrs -> ReversePostOrderFunctionAttrsLegacyPass
in preparation for adding a class ReversePostOrderFunctionAttrs as the pass in the new PM.
(edit: actually wait what? The new class name will be
ReversePostOrderFunctionAttrsPass, so it doesn't conflict. So this step is
sort of useless churn).

llvm/include/llvm/InitializePasses.h
llvm/lib/LTO/LTOCodeGenerator.cpp
llvm/lib/Transforms/IPO/IPO.cpp
llvm/lib/Transforms/IPO/FunctionAttrs.cpp
Rename initializeReversePostOrderFunctionAttrsPass -> initializeReversePostOrderFunctionAttrsLegacyPassPass
(note that the "PassPass" thing falls out of `s/ReversePostOrderFunctionAttrs/ReversePostOrderFunctionAttrsLegacyPass/`)
Note that the INITIALIZE_PASS macro is what creates this identifier name, so renaming the class requires this renaming too.

Note that createReversePostOrderFunctionAttrsPass does not need to be
renamed since its name is not generated from the class name.

3. Add the new PM pass class.

In the new PM all passes need to have their
declaration in a header somewhere, so you will often need to add a header.
In this case
llvm/include/llvm/Transforms/IPO/FunctionAttrs.h is already there because
PostOrderFunctionAttrsPass was already ported.
The file-level comment from the .cpp file can be used as the file-level
comment for the new header. You may want to tweak the wording slightly
from "this file implements" to "this file provides" or similar.

Add declaration for the new PM pass in this header:

    class ReversePostOrderFunctionAttrsPass
        : public PassInfoMixin<ReversePostOrderFunctionAttrsPass> {
    public:
      PreservedAnalyses run(Module &M, AnalysisManager<Module> &AM);
    };

Its name should end with `Pass` for consistency (note that this doesn't
collide with the names of most old PM passes). E.g. call it
`<name of the old PM pass>Pass`.

Also, move the doxygen comment from the old PM pass to the declaration of
this class in the header.
Also, include the declaration for the new PM class
`llvm/Transforms/IPO/FunctionAttrs.h` at the top of the file (in this case,
it was already done when the other pass in this file was ported).

Now define the `run` method for the new class.
The main things here are:
a) Use AM.getResult<...>(M) to get results instead of `getAnalysis<...>()`

b) If the old PM pass would have returned "false" (i.e. `Changed ==
false`), then you should return PreservedAnalyses::all();

c) In the old PM getAnalysisUsage method, observe the calls
   `AU.addPreserved<...>();`.

   In the case `Changed == true`, for each preserved analysis you should do
   call `PA.preserve<...>()` on a PreservedAnalyses object and return it.
   E.g.:

       PreservedAnalyses PA;
       PA.preserve<CallGraphAnalysis>();
       return PA;

Note that calls to skipModule/skipFunction are not supported in the new PM
currently, so optnone and optimization bisect support do not work. You can
just drop those calls for now.

4. Add the pass to the new PM pass registry to make it available in opt.

In llvm/lib/Passes/PassBuilder.cpp add a #include for your header.
`#include "llvm/Transforms/IPO/FunctionAttrs.h"`
In this case there is already an include (from when
PostOrderFunctionAttrsPass was ported).

Add your pass to llvm/lib/Passes/PassRegistry.def
In this case, I added
`MODULE_PASS("rpo-functionattrs", ReversePostOrderFunctionAttrsPass())`
The string is from the `INITIALIZE_PASS*` macros used in the old pass
manager.

Then choose a test that uses the pass and use the new PM `-passes=...` to
run it.
E.g. in this case there is a test that does:
; RUN: opt < %s -basicaa -functionattrs -rpo-functionattrs -S | FileCheck %s
I have added the line:
; RUN: opt < %s -aa-pipeline=basic-aa -passes='require<targetlibinfo>,cgscc(function-attrs),rpo-functionattrs' -S | FileCheck %s
The `-aa-pipeline=basic-aa` and
`require<targetlibinfo>,cgscc(function-attrs)` are what is needed to run
functionattrs in the new PM (note that in the new PM "functionattrs"
becomes "function-attrs" for some reason). This is just pulled from
`readattrs.ll` which contains the change from when functionattrs was ported
to the new PM.
Adding rpo-functionattrs causes the pass that was just ported to run.

llvm-svn: 272505
2016-06-12 07:48:51 +00:00
David Majnemer
89a8ea9137 [CaptureTracking] Volatile operations capture their memory location
The memory location that corresponds to a volatile operation is very
special.  They are observed by the machine in ways which we cannot
reason about.

Differential Revision: http://reviews.llvm.org/D20555

llvm-svn: 270879
2016-05-26 17:36:22 +00:00
Peter Collingbourne
19d18aa6de MemorySSA: Revert r269678 and r268068; replace with special casing in MemorySSA.
It turns out that too many passes are relying on alias analysis results
for control dependencies. Until we fix that by introducing a more accurate
modelling of control dependencies, special case assume in MemorySSA instead.

Also introduce tests to ensure we don't regress the FunctionAttrs or LICM
passes.

Differential Revision: http://reviews.llvm.org/D20658

llvm-svn: 270823
2016-05-26 04:58:46 +00:00
David Majnemer
3c41824d16 [FunctionAttrs] Volatile loads should disable readonly
A volatile load has side effects beyond what callers expect readonly to
signify.  For example, it is not safe to reorder two function calls
which each perform a volatile load to the same memory location.

llvm-svn: 270671
2016-05-25 05:53:04 +00:00
Sanjoy Das
b20d278ebd Don't IPO over functions that can be de-refined
Summary:
Fixes PR26774.

If you're aware of the issue, feel free to skip the "Motivation"
section and jump directly to "This patch".

Motivation:

I define "refinement" as discarding behaviors from a program that the
optimizer has license to discard.  So transforming:

```
void f(unsigned x) {
  unsigned t = 5 / x;
  (void)t;
}
```

to

```
void f(unsigned x) { }
```

is refinement, since the behavior went from "if x == 0 then undefined
else nothing" to "nothing" (the optimizer has license to discard
undefined behavior).

Refinement is a fundamental aspect of many mid-level optimizations done
by LLVM.  For instance, transforming `x == (x + 1)` to `false` also
involves refinement since the expression's value went from "if x is
`undef` then { `true` or `false` } else { `false` }" to "`false`" (by
definition, the optimizer has license to fold `undef` to any non-`undef`
value).

Unfortunately, refinement implies that the optimizer cannot assume
that the implementation of a function it can see has all of the
behavior an unoptimized or a differently optimized version of the same
function can have.  This is a problem for functions with comdat
linkage, where a function can be replaced by an unoptimized or a
differently optimized version of the same source level function.

For instance, FunctionAttrs cannot assume a comdat function is
actually `readnone` even if it does not have any loads or stores in
it; since there may have been loads and stores in the "original
function" that were refined out in the currently visible variant, and
at the link step the linker may in fact choose an implementation with
a load or a store.  As an example, consider a function that does two
atomic loads from the same memory location, and writes to memory only
if the two values are not equal.  The optimizer is allowed to refine
this function by first CSE'ing the two loads, and the folding the
comparision to always report that the two values are equal.  Such a
refined variant will look like it is `readonly`.  However, the
unoptimized version of the function can still write to memory (since
the two loads //can// result in different values), and selecting the
unoptimized version at link time will retroactively invalidate
transforms we may have done under the assumption that the function
does not write to memory.

Note: this is not just a problem with atomics or with linking
differently optimized object files.  See PR26774 for more realistic
examples that involved neither.

This patch:

This change introduces a new set of linkage types, predicated as
`GlobalValue::mayBeDerefined` that returns true if the linkage type
allows a function to be replaced by a differently optimized variant at
link time.  It then changes a set of IPO passes to bail out if they see
such a function.

Reviewers: chandlerc, hfinkel, dexonsmith, joker.eph, rnk

Subscribers: mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D18634

llvm-svn: 265762
2016-04-08 00:48:30 +00:00
Justin Lebar
7e369d0dca [attrs] Handle convergent CallSites.
Summary:
Previously we had a notion of convergent functions but not of convergent
calls.  This is insufficient to correctly analyze calls where the target
is unknown, e.g. indirect calls.

Now a call is convergent if it targets a known-convergent function, or
if it's explicitly marked as convergent.  As usual, we can remove
convergent where we can prove that no convergent operations are
performed in the call.

Originally landed as r261544, then reverted in r261544 for (incidental)
build breakage.  Re-landed here with no changes.

Reviewers: chandlerc, jingyue

Subscribers: llvm-commits, tra, jhen, hfinkel

Differential Revision: http://reviews.llvm.org/D17739

llvm-svn: 263481
2016-03-14 20:18:54 +00:00
Justin Lebar
f84464712c Revert "[attrs] Handle convergent CallSites."
This reverts r261544, which was causing a test failure in
Transforms/FunctionAttrs/readattrs.ll.

llvm-svn: 261549
2016-02-22 18:24:43 +00:00
Justin Lebar
ca379cda9f [attrs] Handle convergent CallSites.
Summary:
Previously we had a notion of convergent functions but not of convergent
calls.  This is insufficient to correctly analyze calls where the target
is unknown, e.g. indirect calls.

Now a call is convergent if it targets a known-convergent function, or
if it's explicitly marked as convergent.  As usual, we can remove
convergent where we can prove that no convergent operations are
performed in the call.

Reviewers: chandlerc, jingyue

Subscribers: hfinkel, jhen, tra, llvm-commits

Differential Revision: http://reviews.llvm.org/D17317

llvm-svn: 261544
2016-02-22 17:51:35 +00:00
Philip Reames
fd1b93f5a6 [CaptureTracking] Add a test case for pointer cmpxchg
This test builds on 261250 (IR support for cmpxchg of pointers) and 261245 (capture tracking support for cmpxchg) to show that correctly analyze the capturing of pointers in a cmpxchg of pointer type.

llvm-svn: 261284
2016-02-19 00:13:09 +00:00
Philip Reames
b731b338c8 [CaptureTracking] Support atomicrmw and cmpxchg
These atomic operations are conceptually both a load and store from the same location. As such, we can treat them as the most conservative of those two components which in practice, means we can treat them like stores. An cmpxchg or atomicrmw captures the values, but not the locations accessed.

Note: We can probably be more aggressive about the comparison value in an cmpxhg since to have it be in memory, it must already be captured, but I figured it was better to avoid that for the moment.

Note 2: It turns out that since we don't actually support cmpxchg of pointer type, writing a negative test is impossible.

Differential Revision: http://reviews.llvm.org/D17400

llvm-svn: 261245
2016-02-18 19:23:27 +00:00
Chandler Carruth
d8a5b5b32e [PM] Port the PostOrderFunctionAttrs pass to the new pass manager and
convert one test to use this.

This is a particularly significant milestone because it required
a working per-function AA framework which can be queried over each
function from within a CGSCC transform pass (and additionally a module
analysis to be accessible). This is essentially *the* point of the
entire pass manager rewrite. A CGSCC transform is able to query for
multiple different function's analysis results. It works. The whole
thing appears to actually work and accomplish the original goal. While
we were able to hack function attrs and basic-aa to "work" in the old
pass manager, this port doesn't use any of that, it directly leverages
the new fundamental functionality.

For this to work, the CGSCC framework also has to support SCC-based
behavior analysis, etc. The only part of the CGSCC pass infrastructure
not sorted out at this point are the updates in the face of inlining and
running function passes that mutate the call graph.

The changes are pretty boring and boiler-plate. Most of the work was
factored into more focused preperatory patches. But this is what wires
it all together.

llvm-svn: 261203
2016-02-18 11:03:11 +00:00
Chandler Carruth
710380f52f [attrs] Move the norecurse deduction to operate on the node set rather
than the SCC object, and have it scan the instruction stream directly
rather than relying on call records.

This makes the behavior of this routine consistent between libc routines
and LLVM intrinsics for libc routines. We can go and start teaching it
about those being norecurse, but we should behave the same for the
intrinsic and the libc routine rather than differently. I chatted with
James Molloy and the inconsistency doesn't seem intentional and likely
is due to intrinsic calls not being modelled in the call graph analyses.

This also fixes a bug where we would deduce norecurse on optnone
functions, when generally we try to handle optnone functions as-if they
were replaceable and thus unanalyzable.

llvm-svn: 260813
2016-02-13 08:47:51 +00:00
Justin Lebar
f16a73d9fa Add convergent-removing bits to FunctionAttrs pass.
Summary:
Remove the convergent attribute on any functions which provably do not
contain or invoke any convergent functions.

After this change, we'll be able to modify clang to conservatively add
'convergent' to all functions when compiling CUDA.

Reviewers:  jingyue, joker.eph

Subscribers: llvm-commits, tra, jhen, hfinkel, resistor, chandlerc, arsenm

Differential Revision: http://reviews.llvm.org/D17013

llvm-svn: 260319
2016-02-09 23:03:22 +00:00
Sanjoy Das
0a3d627330 [FunctionAttrs] Fix SCC logic around operand bundles
FunctionAttrs does an "optimistic" analysis of SCCs as a unit, which
means normally it is able to disregard calls from an SCC into itself.
However, calls and invokes with operand bundles are allowed to have
memory effects not fully described by the memory effects on the call
target, so we can't be optimistic around operand-bundled calls from an
SCC into itself.

llvm-svn: 260244
2016-02-09 18:40:40 +00:00
Chandler Carruth
1b5532dd29 [attrs] Split the late-revisit pattern for deducing norecurse in
a top-down manner into a true top-down or RPO pass over the call graph.

There are specific patterns of function attributes, notably the
norecurse attribute, which are most effectively propagated top-down
because all they us caller information.

Walk in RPO over the call graph SCCs takes the form of a module pass run
immediately after the CGSCC pass managers postorder walk of the SCCs,
trying again to deduce norerucrse for each singular SCC in the call
graph.

This removes a very legacy pass manager specific trick of using a lazy
revisit list traversed during finalization of the CGSCC pass. There is
no analogous finalization step in the new pass manager, and a lazy
revisit list is just trying to produce an RPO iteration of the call
graph. We can do that more directly if more expensively. It seems
unlikely that this will be the expensive part of any compilation though
as we never examine the function bodies here. Even in an LTO run over
a very large module, this should be a reasonable fast set of operations
over a reasonably small working set -- the function call graph itself.

In the future, if this really is a compile time performance issue, we
can look at building support for both post order and RPO traversals
directly into a pass manager that builds and maintains the PO list of
SCCs.

Differential Revision: http://reviews.llvm.org/D15785

llvm-svn: 257163
2016-01-08 10:55:52 +00:00
Chandler Carruth
8beb86a806 [attrs] Extract the pure inference of function attributes into
a standalone pass.

There is no call graph or even interesting analysis for this part of
function attributes -- it is literally inferring attributes based on the
target library identification. As such, we can do it using a much
simpler module pass that just walks the declarations. This can also
happen much earlier in the pass pipeline which has benefits for any
number of other passes.

In the process, I've cleaned up one particular aspect of the logic which
was necessary in order to separate the two passes cleanly. It now counts
inferred attributes independently rather than just counting all the
inferred attributes as one, and the counts are more clearly explained.

The two test cases we had for this code path are both ... woefully
inadequate and copies of each other. I've kept the superset test and
updated it. We need more testing here, but I had to pick somewhere to
stop fixing everything broken I saw here.

Differential Revision: http://reviews.llvm.org/D15676

llvm-svn: 256466
2015-12-27 08:41:34 +00:00
Chandler Carruth
cf6f5436f5 [attrs] Split off the forced attributes utility into its own pass that
is (by default) run much earlier than FuncitonAttrs proper.

This allows forcing optnone or other widely impactful attributes. It is
also a bit simpler as the force attribute behavior needs no specific
iteration order.

I've added the pass into the default module pass pipeline and LTO pass
pipeline which mirrors where function attrs itself was being run.

Differential Revision: http://reviews.llvm.org/D15668

llvm-svn: 256465
2015-12-27 08:13:45 +00:00
James Molloy
b585b0aee8 [FunctionAttrs] Provide a mechanism for adding function attributes from the command line
This provides a way to force a function to have certain attributes from the command line. This can be useful when debugging or doing workload exploration, where manually editing IR is tedious or not possible (due to build systems etc).

The syntax is -force-attribute=function_name:attribute_name

All function attributes are parsed except alignstack as it requires an argument.

llvm-svn: 253550
2015-11-19 08:49:57 +00:00
Elena Demikhovsky
0600baa03e Vector of pointers in function attributes calculation
While setting function attributes we check all instructions that may access memory. For a call instruction we check all arguments. The special check is required for pointers.
I added vector-of-pointers to the call arguments types that should be checked.

Differential Revision: http://reviews.llvm.org/D14693

llvm-svn: 253363
2015-11-17 19:30:51 +00:00
James Molloy
64e756bd07 Revert "Revert "[FunctionAttrs] Identify norecurse functions""
This reapplies this patch, with test fixes.

llvm-svn: 252871
2015-11-12 10:55:20 +00:00
James Molloy
9cd723ec63 Revert "[FunctionAttrs] Identify norecurse functions"
This reverts commit r252862. This introduced test failures and I'm reverting while I investigate how this happened.

llvm-svn: 252863
2015-11-12 09:05:43 +00:00
James Molloy
4da975f03a [FunctionAttrs] Identify norecurse functions
A function can be marked as norecurse if:
  * The SCC to which it belongs has cardinality 1; and either
    a) It does not call any non-norecurse function. This includes self-recursion; or
    b) It only has one callsite and the function that callsite is within is marked norecurse.

a) is best propagated bottom-up and b) is best propagated top-down.

We build up the norecurse attributes bottom-up using the existing SCC pass, and mark functions with no obvious recursion (but not provably norecurse) to sweep later, top-down.

llvm-svn: 252862
2015-11-12 08:53:04 +00:00
Sanjoy Das
9dbcbc0397 [FunctionAttrs] Fix an iterator wraparound bug
Summary:
This change fixes an iterator wraparound bug in
`determinePointerReadAttrs`.

Ideally, ++'ing off the `end()` of an iplist should result in a failed
assert, but currently iplist seems to silently wrap to the head of the
list on `end()++`.  This is why the bad behavior is difficult to
demonstrate.

Reviewers: chandlerc, reames

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D14350

llvm-svn: 252386
2015-11-07 01:55:53 +00:00
Philip Reames
c1eca23247 [FunctionAttr] Infer nonnull attributes on returns
Teach FunctionAttr to infer the nonnull attribute on return values of functions which never return a potentially null value. This is done both via a conservative local analysis for the function itself and a optimistic per-SCC analysis. If no function in the SCC returns anything which could be null (other than values from other functions in the SCC), we can conclude no function returned a null pointer. Even if some function within the SCC returns a null pointer, we may be able to locally conclude that some don't.

Differential Revision: http://reviews.llvm.org/D9688

llvm-svn: 246476
2015-08-31 19:44:38 +00:00
David Majnemer
c8b1f095a3 Move the personality function from LandingPadInst to Function
The personality routine currently lives in the LandingPadInst.

This isn't desirable because:
- All LandingPadInsts in the same function must have the same
  personality routine.  This means that each LandingPadInst beyond the
  first has an operand which produces no additional information.

- There is ongoing work to introduce EH IR constructs other than
  LandingPadInst.  Moving the personality routine off of any one
  particular Instruction and onto the parent function seems a lot better
  than have N different places a personality function can sneak onto an
  exceptional function.

Differential Revision: http://reviews.llvm.org/D10429

llvm-svn: 239940
2015-06-17 20:52:32 +00:00
Bjorn Steinbrink
8603eb4818 Remove conflicting attributes before adding deduced readonly/readnone
Summary:
In case of functions that have a pointer argument and only pass it to
each other, the function attributes pass deduces that the pointer should
get the readnone attribute, but fails to remove a readonly attribute
that may already have been present.

Reviewers: nlewycky

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D9995

llvm-svn: 238152
2015-05-25 19:46:38 +00:00
David Blaikie
dfadb4e9ee [opaque pointer type] Add textual IR support for explicit type parameter to the call instruction
See r230786 and r230794 for similar changes to gep and load
respectively.

Call is a bit different because it often doesn't have a single explicit
type - usually the type is deduced from the arguments, and just the
return type is explicit. In those cases there's no need to change the
IR.

When that's not the case, the IR usually contains the pointer type of
the first operand - but since typed pointers are going away, that
representation is insufficient so I'm just stripping the "pointerness"
of the explicit type away.

This does make the IR a bit weird - it /sort of/ reads like the type of
the first operand: "call void () %x(" but %x is actually of type "void
()*" and will eventually be just of type "ptr". But this seems not too
bad and I don't think it would benefit from repeating the type
("void (), void () * %x(" and then eventually "void (), ptr %x(") as has
been done with gep and load.

This also has a side benefit: since the explicit type is no longer a
pointer, there's no ambiguity between an explicit type and a function
that returns a function pointer. Previously this case needed an explicit
type (eg: a function returning a void() function was written as
"call void () () * @x(" rather than "call void () * @x(" because of the
ambiguity between a function returning a pointer to a void() function
and a function returning void).

No ambiguity means even function pointer return types can just be
written alone, without writing the whole function's type.

This leaves /only/ the varargs case where the explicit type is required.

Given the special type syntax in call instructions, the regex-fu used
for migration was a bit more involved in its own unique way (as every
one of these is) so here it is. Use it in conjunction with the apply.sh
script and associated find/xargs commands I've provided in rr230786 to
migrate your out of tree tests. Do let me know if any of this doesn't
cover your cases & we can iterate on a more general script/regexes to
help others with out of tree tests.

About 9 test cases couldn't be automatically migrated - half of those
were functions returning function pointers, where I just had to manually
delete the function argument types now that we didn't need an explicit
function type there. The other half were typedefs of function types used
in calls - just had to manually drop the * from those.

import fileinput
import sys
import re

pat = re.compile(r'((?:=|:|^|\s)call\s(?:[^@]*?))(\s*$|\s*(?:(?:\[\[[a-zA-Z0-9_]+\]\]|[@%](?:(")?[\\\?@a-zA-Z0-9_.]*?(?(3)"|)|{{.*}}))(?:\(|$)|undef|inttoptr|bitcast|null|asm).*$)')
addrspace_end = re.compile(r"addrspace\(\d+\)\s*\*$")
func_end = re.compile("(?:void.*|\)\s*)\*$")

def conv(match, line):
  if not match or re.search(addrspace_end, match.group(1)) or not re.search(func_end, match.group(1)):
    return line
  return line[:match.start()] + match.group(1)[:match.group(1).rfind('*')].rstrip() + match.group(2) + line[match.end():]

for line in sys.stdin:
  sys.stdout.write(conv(re.search(pat, line), line))

llvm-svn: 235145
2015-04-16 23:24:18 +00:00
David Blaikie
ab043ff680 [opaque pointer type] Add textual IR support for explicit type parameter to load instruction
Essentially the same as the GEP change in r230786.

A similar migration script can be used to update test cases, though a few more
test case improvements/changes were required this time around: (r229269-r229278)

import fileinput
import sys
import re

pat = re.compile(r"((?:=|:|^)\s*load (?:atomic )?(?:volatile )?(.*?))(| addrspace\(\d+\) *)\*($| *(?:%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|\[\[[a-zA-Z]|\{\{).*$)")

for line in sys.stdin:
  sys.stdout.write(re.sub(pat, r"\1, \2\3*\4", line))

Reviewers: rafael, dexonsmith, grosser

Differential Revision: http://reviews.llvm.org/D7649

llvm-svn: 230794
2015-02-27 21:17:42 +00:00
David Blaikie
0d99339102 [opaque pointer type] Add textual IR support for explicit type parameter to getelementptr instruction
One of several parallel first steps to remove the target type of pointers,
replacing them with a single opaque pointer type.

This adds an explicit type parameter to the gep instruction so that when the
first parameter becomes an opaque pointer type, the type to gep through is
still available to the instructions.

* This doesn't modify gep operators, only instructions (operators will be
  handled separately)

* Textual IR changes only. Bitcode (including upgrade) and changing the
  in-memory representation will be in separate changes.

* geps of vectors are transformed as:
    getelementptr <4 x float*> %x, ...
  ->getelementptr float, <4 x float*> %x, ...
  Then, once the opaque pointer type is introduced, this will ultimately look
  like:
    getelementptr float, <4 x ptr> %x
  with the unambiguous interpretation that it is a vector of pointers to float.

* address spaces remain on the pointer, not the type:
    getelementptr float addrspace(1)* %x
  ->getelementptr float, float addrspace(1)* %x
  Then, eventually:
    getelementptr float, ptr addrspace(1) %x

Importantly, the massive amount of test case churn has been automated by
same crappy python code. I had to manually update a few test cases that
wouldn't fit the script's model (r228970,r229196,r229197,r229198). The
python script just massages stdin and writes the result to stdout, I
then wrapped that in a shell script to handle replacing files, then
using the usual find+xargs to migrate all the files.

update.py:
import fileinput
import sys
import re

ibrep = re.compile(r"(^.*?[^%\w]getelementptr inbounds )(((?:<\d* x )?)(.*?)(| addrspace\(\d\)) *\*(|>)(?:$| *(?:%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|\[\[[a-zA-Z]|\{\{).*$))")
normrep = re.compile(       r"(^.*?[^%\w]getelementptr )(((?:<\d* x )?)(.*?)(| addrspace\(\d\)) *\*(|>)(?:$| *(?:%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|\[\[[a-zA-Z]|\{\{).*$))")

def conv(match, line):
  if not match:
    return line
  line = match.groups()[0]
  if len(match.groups()[5]) == 0:
    line += match.groups()[2]
  line += match.groups()[3]
  line += ", "
  line += match.groups()[1]
  line += "\n"
  return line

for line in sys.stdin:
  if line.find("getelementptr ") == line.find("getelementptr inbounds"):
    if line.find("getelementptr inbounds") != line.find("getelementptr inbounds ("):
      line = conv(re.match(ibrep, line), line)
  elif line.find("getelementptr ") != line.find("getelementptr ("):
    line = conv(re.match(normrep, line), line)
  sys.stdout.write(line)

apply.sh:
for name in "$@"
do
  python3 `dirname "$0"`/update.py < "$name" > "$name.tmp" && mv "$name.tmp" "$name"
  rm -f "$name.tmp"
done

The actual commands:
From llvm/src:
find test/ -name *.ll | xargs ./apply.sh
From llvm/src/tools/clang:
find test/ -name *.mm -o -name *.m -o -name *.cpp -o -name *.c | xargs -I '{}' ../../apply.sh "{}"
From llvm/src/tools/polly:
find test/ -name *.ll | xargs ./apply.sh

After that, check-all (with llvm, clang, clang-tools-extra, lld,
compiler-rt, and polly all checked out).

The extra 'rm' in the apply.sh script is due to a few files in clang's test
suite using interesting unicode stuff that my python script was throwing
exceptions on. None of those files needed to be migrated, so it seemed
sufficient to ignore those cases.

Reviewers: rafael, dexonsmith, grosser

Differential Revision: http://reviews.llvm.org/D7636

llvm-svn: 230786
2015-02-27 19:29:02 +00:00
Paul Robinson
2b27bd26b6 Normally an 'optnone' function goes through fast-isel, which does not
call DAGCombiner. But we ran into a case (on Windows) where the
calling convention causes argument lowering to bail out of fast-isel,
and we end up in CodeGenAndEmitDAG() which does run DAGCombiner.
So, we need to make DAGCombiner check for 'optnone' after all.

Commit includes the test that found this, plus another one that got
missed in the original optnone work.

llvm-svn: 221168
2014-11-03 18:19:26 +00:00
Chandler Carruth
5652971ecf [optnone] Make the optnone attribute effective at suppressing function
attribute and function argument attribute synthesizing and propagating.

As with the other uses of this attribute, the goal remains a best-effort
(no guarantees) attempt to not optimize the function or assume things
about the function when optimizing. This is particularly useful for
compiler testing, bisecting miscompiles, triaging things, etc. I was
hitting specific issues using optnone to isolate test code from a test
driver for my fuzz testing, and this is one step of fixing that.

llvm-svn: 215538
2014-08-13 10:49:33 +00:00
Nick Lewycky
cf5b9e086e When analyzing params/args for readnone/readonly, don't forget to consider that a pointer argument may be passed through a callsite to the return, and that we may need to analyze it. Fixes a bug reported on llvm-dev: http://lists.cs.uiuc.edu/pipermail/llvmdev/2014-May/073098.html
llvm-svn: 209870
2014-05-30 02:31:27 +00:00
Reid Kleckner
c9ab4a9a3b Update optimization passes to handle inalloca arguments
Summary:
I searched Transforms/ and Analysis/ for 'ByVal' and updated those call
sites to check for inalloca if appropriate.

I added tests for any change that would allow an optimization to fire on
inalloca.

Reviewers: nlewycky

Differential Revision: http://llvm-reviews.chandlerc.com/D2449

llvm-svn: 200281
2014-01-28 02:38:36 +00:00
Matt Arsenault
50ba8b89a7 Make nocapture analysis work with addrspacecast
llvm-svn: 199246
2014-01-14 19:11:52 +00:00
Daniel Dunbar
a496d61c01 [tests] Cleanup initialization of test suffixes.
- Instead of setting the suffixes in a bunch of places, just set one master
   list in the top-level config. We now only modify the suffix list in a few
   suites that have one particular unique suffix (.ml, .mc, .yaml, .td, .py).

 - Aside from removing the need for a bunch of lit.local.cfg files, this enables
   4 tests that were inadvertently being skipped (one in
   Transforms/BranchFolding, a .s file each in DebugInfo/AArch64 and
   CodeGen/PowerPC, and one in CodeGen/SI which is now failing and has been
   XFAILED).

 - This commit also fixes a bunch of config files to use config.root instead of
   older copy-pasted code.

llvm-svn: 188513
2013-08-16 00:37:11 +00:00
Tim Northover
67f2cc8ebf Fix FileCheck --check-prefix lines.
Various tests had sprung up over the years which had --check-prefix=ABC on the
RUN line, but "CHECK-ABC:" later on. This happened to work before, but was
strictly incorrect. FileCheck is getting stricter soon though.

Patch by Ron Ofir.

llvm-svn: 188173
2013-08-12 12:43:26 +00:00
Stephen Lin
cf082ae903 Update Transforms tests to use CHECK-LABEL for easier debugging. No functionality change.
This update was done with the following bash script:

  find test/Transforms -name "*.ll" | \
  while read NAME; do
    echo "$NAME"
    if ! grep -q "^; *RUN: *llc" $NAME; then
      TEMP=`mktemp -t temp`
      cp $NAME $TEMP
      sed -n "s/^define [^@]*@\([A-Za-z0-9_]*\)(.*$/\1/p" < $NAME | \
      while read FUNC; do
        sed -i '' "s/;\(.*\)\([A-Za-z0-9_]*\):\( *\)@$FUNC\([( ]*\)\$/;\1\2-LABEL:\3@$FUNC(/g" $TEMP
      done
      mv $TEMP $NAME
    fi
  done

llvm-svn: 186268
2013-07-14 01:42:54 +00:00
Nick Lewycky
7b093a1c2f Extend 'readonly' and 'readnone' to work on function arguments as well as
functions. Make the function attributes pass add it to known library functions
and when it can deduce it.

llvm-svn: 185735
2013-07-06 00:29:58 +00:00
Michael Gottesman
5165cfc3e1 Change the gettimeofday test to only test on a posix platform.
llvm-svn: 185503
2013-07-03 04:15:22 +00:00
Michael Gottesman
5a59133d77 Added support in FunctionAttrs for adding relevant function/argument attributes for the posix call gettimeofday.
This implies annotating it as nounwind and its arguments as nocapture. To be
conservative, we do not annotate the arguments with noalias since some platforms
do not have restrict on the declaration for gettimeofday.

llvm-svn: 185502
2013-07-03 04:00:54 +00:00