Commit Graph

231 Commits

Author SHA1 Message Date
Kamil Rytarowski cce21c1dfe Make shell redirection construct portable
Summary:
NetBSD shell sh(1) does not support ">& /dev/null" construct.
This is bashism. The portable and POSIX solution is to use:
"> /dev/null 2>&1".

This change fixes 22 Unexpected Failures on NetBSD/amd64
for the "check-llvm" target.

Sponsored by <The NetBSD Foundation>

Reviewers: joerg, dim, rnk

Reviewed By: joerg, rnk

Subscribers: rnk, davide, llvm-commits

Differential Revision: https://reviews.llvm.org/D35277

llvm-svn: 307789
2017-07-12 13:24:46 +00:00
Michael Kruse 47f856095a [BasicAA] Use MayAlias instead of PartialAlias for fallback.
Using various methods, BasicAA tries to determine whether two
GetElementPtr memory locations alias when its base pointers are known
to be equal. When none of its heuristics are applicable, it falls back
to PartialAlias to, according to a comment, protect TBAA making a wrong
decision in case of unions and malloc. PartialAlias is not correct,
because a PartialAlias result implies that some, but not all, bytes
overlap which is not necessarily the case here.

AAResults returns the first analysis result that is not MayAlias.
BasicAA is always the first alias analysis. When it returns
PartialAlias, no other analysis is queried to give a more exact result
(which was the intention of returning PartialAlias instead of MayAlias).
For instance, ScopedAA could return a more accurate result.

The PartialAlias hack was introduced in r131781 (and re-applied in
r132632 after some reverts) to fix llvm.org/PR9971 where TBAA returns a
wrong NoAlias result due to a union. A test case for the malloc case
mentioned in the comment was not provided and I don't think it is
affected since it returns an omnipotent char anyway.

Since r303851 (https://reviews.llvm.org/D33328) clang does emit specific
TBAA for unions anymore (but "omnipotent char" instead). Hence, the
PartialAlias workaround is not required anymore.

This patch passes the test-suite and check-llvm/check-clang of a
self-hoisted build on x64.

Reviewed By: hfinkel

Differential Revision: https://reviews.llvm.org/D34318

llvm-svn: 305938
2017-06-21 18:25:37 +00:00
Daniel Jasper 61fa0dcac3 Add '#' to test regex that I forgot in r303025.
llvm-svn: 303034
2017-05-15 04:58:27 +00:00
Daniel Jasper 54392a20a2 Fix two tests that weren't correctly copied.
One didn't correctly fine the regex variable, the other still had a RUN
line for FNOBUILTIN-checks, which weren't copied to the file.

llvm-svn: 303025
2017-05-14 22:07:50 +00:00
Justin Bogner b713266331 AA: Use generic intrinsics for tests instead of target specific ones
Update a few tests to use llvm.masked.load/store instead of arm neon
vector loads and stores, and move the tests that are actually specific
to those arm intrinsics to their own files. This lets us mark the
tests that use target specific intrinsics as requiring those targets.

llvm-svn: 302972
2017-05-13 00:12:52 +00:00
Matt Arsenault f10061ec70 Add address space mangling to lifetime intrinsics
In preparation for allowing allocas to have non-0 addrspace.

llvm-svn: 299876
2017-04-10 20:18:21 +00:00
Igor Laevsky 37cba43604 [BasicAA] Take attributes into account when requesting modref info for a call site
Differential Revision: https://reviews.llvm.org/D29989

llvm-svn: 296617
2017-03-01 13:19:51 +00:00
Mehdi Amini 1726fc698c Fix BasicAA incorrect assumption on GEP
This is fixing pr31761: BasicAA is deducing NoAlias
on the result of the GEP if the base pointer is itself NoAlias.

This is possible only if the NoAlias on the base pointer is
deduced with a non-sized query: this should guarantee that
the pointers are belonging to different memory allocation
and that the GEP can't legally jump from one to another.

Differential Revision: https://reviews.llvm.org/D29216

llvm-svn: 293293
2017-01-27 16:12:22 +00:00
Chandler Carruth 7a73eabf64 [PM] Add more dedicated testing to cover the invalidation logic added to
BasicAA in r290603.

I've kept the basic testing in the new PM test file as that also covers
the AAManager invalidation logic. If/when there is a good place for
broader AA testing it could move there.

This test is somewhat unsatisfying as I can't get it to fail even with
ASan outside of explicit checks of the invalidation. Apparently we don't
yet have any test coverage of the BasicAA code paths using either the
domtree or loopinfo -- I made both of them always be null and check-llvm
passed.

llvm-svn: 290612
2016-12-27 17:59:22 +00:00
Bryant Wong a07d9b1460 [AliasAnalysis] Teach BasicAA about memcpy.
Differential Revision: https://reviews.llvm.org/D27034

llvm-svn: 290526
2016-12-25 22:42:27 +00:00
Sanjoy Das 3336f681e3 [Verifier] Add verification for TBAA metadata
Summary:
This change adds some verification in the IR verifier around struct path
TBAA metadata.

Other than some basic sanity checks (e.g. we get constant integers where
we expect constant integers), this checks:

 - That by the time an struct access tuple `(base-type, offset)` is
   "reduced" to a scalar base type, the offset is `0`.  For instance, in
   C++ you can't start from, say `("struct-a", 16)`, and end up with
   `("int", 4)` -- by the time the base type is `"int"`, the offset
   better be zero.  In particular, a variant of this invariant is needed
   for `llvm::getMostGenericTBAA` to be correct.

 - That there are no cycles in a struct path.

 - That struct type nodes have their offsets listed in an ascending
   order.

 - That when generating the struct access path, you eventually reach the
   access type listed in the tbaa tag node.

Reviewers: dexonsmith, chandlerc, reames, mehdi_amini, manmanren

Subscribers: mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D26438

llvm-svn: 289402
2016-12-11 20:07:15 +00:00
Andrew Kaylor 9604f34996 [BasicAA] Teach BasicAA to handle the inaccessiblememonly and inaccessiblemem_or_argmemonly attributes
Differential Revision: https://reviews.llvm.org/D26382

llvm-svn: 286294
2016-11-08 21:07:42 +00:00
Gerolf Hoflehner 9e2afa8bd7 [BasicAA] Fix - missed alias in GEP expressions
In BasicAA GEP operand values get adjusted ("wrap-around") based on the
pointersize. Otherwise, in non-64b modes, AA could report false negatives.
However, a wrap-around is valid only for a fully evaluated expression.
It had been introduced to fix an alias problem in
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160118/326163.html.
This commit restricts the wrap-around to constant gep operands only where the
value is known at compile-time.

llvm-svn: 284908
2016-10-22 02:41:39 +00:00
Hal Finkel 5c12d8fe8f BasicAA should look through functions with returned arguments
Motivated by the work on the llvm.noalias intrinsic, teach BasicAA to look
through returned-argument functions when answering queries. This is essential
so that we don't loose all other AA information when supplementing with
llvm.noalias.

Differential Revision: http://reviews.llvm.org/D9383

llvm-svn: 275035
2016-07-11 01:32:20 +00:00
Nicolai Haehnle 84c9f9919a Add writeonly IR attribute
Summary:
This complements the earlier addition of IntrWriteMem and IntrWriteArgMem
LLVM intrinsic properties, see D18291.

Also start using the attribute for memset, memcpy, and memmove intrinsics,
and remove their special-casing in BasicAliasAnalysis.

Reviewers: reames, joker.eph

Subscribers: joker.eph, llvm-commits

Differential Revision: http://reviews.llvm.org/D18714

llvm-svn: 274485
2016-07-04 08:01:29 +00:00
Daniel Berlin 73694bb92b Revert "Claim NoAlias if two GEPs index different fields of the same struct"
This reverts commit 2d5d6493f43eb68493a3852b8c226ac9fafdc7eb.

llvm-svn: 271422
2016-06-01 18:55:32 +00:00
Daniel Berlin e846c9dc52 Claim NoAlias if two GEPs index different fields of the same struct
Patch by Taewook Oh

Summary: Patch for Bug 27478. Make BasicAliasAnalysis claims NoAlias if two GEPs index different fields of the same structure.

Reviewers: hfinkel, dberlin

Subscribers: dberlin, mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D20665

llvm-svn: 271415
2016-06-01 18:12:01 +00:00
Michael Kuperstein ae21491819 [BasicAA] Extend inbound GEP negative offset logic to GlobalVariables
r270777 improved the precision of alloca vs. inbounbds GEP alias queries: if
we have (a) an inbounds GEP and (b) a pointer based on an alloca, and the
beginning of the object the GEP points to would have a negative offset with
respect to the alloca, then the GEP can not alias pointer (b).

This makes the same logic fire when (b) is based on a GlobalVariable instead
of an alloca.

Differential Revision: http://reviews.llvm.org/D20652

llvm-svn: 270893
2016-05-26 19:30:49 +00:00
Michael Kuperstein 82069c44ca [BasicAA] Improve precision of alloca vs. inbounds GEP alias queries
If a we have (a) a GEP and (b) a pointer based on an alloca, and the
beginning of the object the GEP points would have a negative offset with
repsect to the alloca, then the GEP can not alias pointer (b).

For example, consider code like:

struct { int f0, int f1, ...} foo;
...
foo alloca;
foo *random = bar(alloca);
int *f0 = &alloca.f0
int *f1 = &random->f1;

Which is lowered, approximately, to:
%alloca = alloca %struct.foo
%random = call %struct.foo* @random(%struct.foo* %alloca)
%f0 = getelementptr inbounds %struct, %struct.foo* %alloca, i32 0, i32 0
%f1 = getelementptr inbounds %struct, %struct.foo* %random, i32 0, i32 1

Assume %f1 and %f0 alias. Then %f1 would point into the object allocated
by %alloca. Since the %f1 GEP is inbounds, that means %random must also
point into the same object. But since %f0 points to the beginning of %alloca,
the highest %f1 can be is (%alloca + 3). This means %random can not be higher
than (%alloca - 1), and so is not inbounds, a contradiction.

Differential Revision: http://reviews.llvm.org/D20495

llvm-svn: 270777
2016-05-25 22:23:08 +00:00
Vedant Kumar ee20294af5 [BasicAA] Compare GEP indices based on value (Fix PR27418)
Equivalent GEP indices with different types are treated as different
indices altogether, leading to an incorrect AA result. Fix the issue
by comparing indices based on their values.

Thanks to Mikael Holmén for reporting the issue!

Differential Revision: http://reviews.llvm.org/D19935

llvm-svn: 269197
2016-05-11 15:45:43 +00:00
Sanjoy Das d47f42435a [BasicAA] Guard intrinsics don't write to memory
Summary:
The idea is very close to what we do for assume intrinsics: we mark the
guard intrinsics as writing to arbitrary memory to maintain control
dependence, but under the covers we teach AA that they do not mod any
particular memory location.

Reviewers: chandlerc, hfinkel, gbiv, reames

Subscribers: george.burgess.iv, mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D19575

llvm-svn: 269007
2016-05-10 02:35:41 +00:00
Chandler Carruth 4f846a5f15 [PM/AA] Port alias analysis evaluator to the new pass manager, and use
it to actually test the new pass manager AA wiring.

This patch was extracted from the (somewhat too large) D12357 and
rebosed on top of the slightly different design of the new pass manager
AA wiring that I just landed. With this we can start testing the AA in
a thorough way with the new pass manager.

Some minor cleanups to the code in the pass was necessitated here, but
otherwise it is a very minimal change.

Differential Revision: http://reviews.llvm.org/D17372

llvm-svn: 261403
2016-02-20 03:46:03 +00:00
Gerolf Hoflehner 87ddb65fa6 [BasicAA] Fix for missing must alias (D16343)
llvm-svn: 259299
2016-01-30 05:52:53 +00:00
Philip Reames ae050a5703 [BasicAA] Remove special casing of memset_pattern16 in favor of generic attribute inference
Most of the properties of memset_pattern16 can be now covered by the generic attributes and inferred by InferFunctionAttrs.  The only exceptions are:
- We don't yet have a writeonly attribute for the first argument.
- We don't have an attribute for modeling the access size facts encoded in MemoryLocation.cpp.  

Differential Revision: http://reviews.llvm.org/D15879

llvm-svn: 256911
2016-01-06 04:53:16 +00:00
Pete Cooper 67cf9a723b Revert "Change memcpy/memset/memmove to have dest and source alignments."
This reverts commit r253511.

This likely broke the bots in
http://lab.llvm.org:8011/builders/clang-ppc64-elf-linux2/builds/20202
http://bb.pgr.jp/builders/clang-3stage-i686-linux/builds/3787

llvm-svn: 253543
2015-11-19 05:56:52 +00:00
Pete Cooper 72bc23ef02 Change memcpy/memset/memmove to have dest and source alignments.
Note, this was reviewed (and more details are in) http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20151109/312083.html

These intrinsics currently have an explicit alignment argument which is
required to be a constant integer.  It represents the alignment of the
source and dest, and so must be the minimum of those.

This change allows source and dest to each have their own alignments
by using the alignment attribute on their arguments.  The alignment
argument itself is removed.

There are a few places in the code for which the code needs to be
checked by an expert as to whether using only src/dest alignment is
safe.  For those places, they currently take the minimum of src/dest
alignments which matches the current behaviour.

For example, code which used to read:
  call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dest, i8* %src, i32 500, i32 8, i1 false)
will now read:
  call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 8 %dest, i8* align 8 %src, i32 500, i1 false)

For out of tree owners, I was able to strip alignment from calls using sed by replacing:
  (call.*llvm\.memset.*)i32\ [0-9]*\,\ i1 false\)
with:
  $1i1 false)

and similarly for memmove and memcpy.

I then added back in alignment to test cases which needed it.

A similar commit will be made to clang which actually has many differences in alignment as now
IRBuilder can generate different source/dest alignments on calls.

In IRBuilder itself, a new argument was added.  Instead of calling:
  CreateMemCpy(Dst, Src, getInt64(Size), DstAlign, /* isVolatile */ false)
you now call
  CreateMemCpy(Dst, Src, getInt64(Size), DstAlign, SrcAlign, /* isVolatile */ false)

There is a temporary class (IntegerAlignment) which takes the source alignment and rejects
implicit conversion from bool.  This is to prevent isVolatile here from passing its default
parameter to the source alignment.

Note, changes in future can now be made to codegen.  I didn't change anything here, but this
change should enable better memcpy code sequences.

Reviewed by Hal Finkel.

llvm-svn: 253511
2015-11-18 22:17:24 +00:00
Akira Hatanaka 5dda592643 Sort the enums in Attributes.h in case insensitive alphabetical order.
Sort the enums in preparation for moving the attributes to a table-gen
file.

rdar://problem/19836465

llvm-svn: 252692
2015-11-11 02:11:46 +00:00
Igor Laevsky 559d170021 [AliasAnalysis] Take into account readnone attribute for the function arguments
Differential Revision: http://reviews.llvm.org/D13992

llvm-svn: 251535
2015-10-28 17:54:48 +00:00
Igor Laevsky 36e84c0fc7 [AliasAnalysis] Take into account readonly attribute for the function arguments
In getArgModRefInfo we consider all arguments as having MRI_ModRef.
However for arguments marked with readonly attribute we can return 
more precise answer - MRI_Ref.

Differential Revision: http://reviews.llvm.org/D13992

llvm-svn: 251525
2015-10-28 16:42:00 +00:00
James Molloy 05a896a8d1 [BasicAA] Bugfix for r251016
If the loaded type sizes don't match the element type of the sequential type, all bets are off and the addresses may, indeed, overlap.

Surprisingly, this just got caught in one test, on one builder, out of the 30+ builders testing this change. Congratulations go to http://lab.llvm.org:8011/builders/clang-aarch64-lnt/builds/5205.

llvm-svn: 251112
2015-10-23 14:17:03 +00:00
James Molloy 5a4d8cd519 [BasicAA] Non-equal indices in a GEP of a SequentialType don't overlap
If the final indices of two GEPs can be proven to not be equal, and
the GEP is of a SequentialType (not a StructType), then the two GEPs
do not alias.

llvm-svn: 251016
2015-10-22 13:28:18 +00:00
Jeroen Ketema ab99b59e8c [ARM][NEON] Use address space in vld([1234]|[234]lane) and vst([1234]|[234]lane) instructions
This commit changes the interface of the vld[1234], vld[234]lane, and vst[1234],
vst[234]lane ARM neon intrinsics and associates an address space with the
pointer that these intrinsics take. This changes, e.g.,

<2 x i32> @llvm.arm.neon.vld1.v2i32(i8*, i32)

to

<2 x i32> @llvm.arm.neon.vld1.v2i32.p0i8(i8*, i32)

This change ensures that address spaces are fully taken into account in the ARM
target during lowering of interleaved loads and stores.

Differential Revision: http://reviews.llvm.org/D12985

llvm-svn: 248887
2015-09-30 10:56:37 +00:00
David Blaikie 2f40830dde [opaque pointer type] Add textual IR support for explicit type parameter for global aliases
update.py:
import fileinput
import sys
import re

alias_match_prefix = r"(.*(?:=|:|^)\s*(?:external |)(?:(?:private|internal|linkonce|linkonce_odr|weak|weak_odr|common|appending|extern_weak|available_externally) )?(?:default |hidden |protected )?(?:dllimport |dllexport )?(?:unnamed_addr |)(?:thread_local(?:\([a-z]*\))? )?alias"
plain = re.compile(alias_match_prefix + r" (.*?))(| addrspace\(\d+\) *)\*($| *(?:%|@|null|undef|blockaddress|addrspacecast|\[\[[a-zA-Z]|\{\{).*$)")
cast  = re.compile(alias_match_prefix + r") ((?:bitcast|inttoptr|addrspacecast)\s*\(.* to (.*?)(| addrspace\(\d+\) *)\*\)\s*(?:;.*)?$)")
gep   = re.compile(alias_match_prefix + r") ((?:getelementptr)\s*(?:inbounds)?\s*\((?P<type>.*), (?P=type)(?:\s*addrspace\(\d+\)\s*)?\* .*\)\s*(?:;.*)?$)")

def conv(line):
  m = re.match(cast, line)
  if m:
    return m.group(1) + " " + m.group(3) + ", " + m.group(2)
  m = re.match(gep, line)
  if m:
    return m.group(1) + " " + m.group(3) + ", " + m.group(2)
  m = re.match(plain, line)
  if m:
    return m.group(1) + ", " + m.group(2) + m.group(3) + "*" + m.group(4) + "\n"
  return line

for line in sys.stdin:
  sys.stdout.write(conv(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

llvm-svn: 247378
2015-09-11 03:22:04 +00:00
Chandler Carruth 7b560d40bd [PM/AA] Rebuild LLVM's alias analysis infrastructure in a way compatible
with the new pass manager, and no longer relying on analysis groups.

This builds essentially a ground-up new AA infrastructure stack for
LLVM. The core ideas are the same that are used throughout the new pass
manager: type erased polymorphism and direct composition. The design is
as follows:

- FunctionAAResults is a type-erasing alias analysis results aggregation
  interface to walk a single query across a range of results from
  different alias analyses. Currently this is function-specific as we
  always assume that aliasing queries are *within* a function.

- AAResultBase is a CRTP utility providing stub implementations of
  various parts of the alias analysis result concept, notably in several
  cases in terms of other more general parts of the interface. This can
  be used to implement only a narrow part of the interface rather than
  the entire interface. This isn't really ideal, this logic should be
  hoisted into FunctionAAResults as currently it will cause
  a significant amount of redundant work, but it faithfully models the
  behavior of the prior infrastructure.

- All the alias analysis passes are ported to be wrapper passes for the
  legacy PM and new-style analysis passes for the new PM with a shared
  result object. In some cases (most notably CFL), this is an extremely
  naive approach that we should revisit when we can specialize for the
  new pass manager.

- BasicAA has been restructured to reflect that it is much more
  fundamentally a function analysis because it uses dominator trees and
  loop info that need to be constructed for each function.

All of the references to getting alias analysis results have been
updated to use the new aggregation interface. All the preservation and
other pass management code has been updated accordingly.

The way the FunctionAAResultsWrapperPass works is to detect the
available alias analyses when run, and add them to the results object.
This means that we should be able to continue to respect when various
passes are added to the pipeline, for example adding CFL or adding TBAA
passes should just cause their results to be available and to get folded
into this. The exception to this rule is BasicAA which really needs to
be a function pass due to using dominator trees and loop info. As
a consequence, the FunctionAAResultsWrapperPass directly depends on
BasicAA and always includes it in the aggregation.

This has significant implications for preserving analyses. Generally,
most passes shouldn't bother preserving FunctionAAResultsWrapperPass
because rebuilding the results just updates the set of known AA passes.
The exception to this rule are LoopPass instances which need to preserve
all the function analyses that the loop pass manager will end up
needing. This means preserving both BasicAAWrapperPass and the
aggregating FunctionAAResultsWrapperPass.

Now, when preserving an alias analysis, you do so by directly preserving
that analysis. This is only necessary for non-immutable-pass-provided
alias analyses though, and there are only three of interest: BasicAA,
GlobalsAA (formerly GlobalsModRef), and SCEVAA. Usually BasicAA is
preserved when needed because it (like DominatorTree and LoopInfo) is
marked as a CFG-only pass. I've expanded GlobalsAA into the preserved
set everywhere we previously were preserving all of AliasAnalysis, and
I've added SCEVAA in the intersection of that with where we preserve
SCEV itself.

One significant challenge to all of this is that the CGSCC passes were
actually using the alias analysis implementations by taking advantage of
a pretty amazing set of loop holes in the old pass manager's analysis
management code which allowed analysis groups to slide through in many
cases. Moving away from analysis groups makes this problem much more
obvious. To fix it, I've leveraged the flexibility the design of the new
PM components provides to just directly construct the relevant alias
analyses for the relevant functions in the IPO passes that need them.
This is a bit hacky, but should go away with the new pass manager, and
is already in many ways cleaner than the prior state.

Another significant challenge is that various facilities of the old
alias analysis infrastructure just don't fit any more. The most
significant of these is the alias analysis 'counter' pass. That pass
relied on the ability to snoop on AA queries at different points in the
analysis group chain. Instead, I'm planning to build printing
functionality directly into the aggregation layer. I've not included
that in this patch merely to keep it smaller.

Note that all of this needs a nearly complete rewrite of the AA
documentation. I'm planning to do that, but I'd like to make sure the
new design settles, and to flesh out a bit more of what it looks like in
the new pass manager first.

Differential Revision: http://reviews.llvm.org/D12080

llvm-svn: 247167
2015-09-09 17:55:00 +00:00
Quentin Colombet 5989bc6f41 [BasicAA] Fix the handling of sext and zext in the analysis of GEPs.
Hopefully this will end the GEPs saga!

This commit reverts r245394, i.e., it reapplies r221876 while incorporating the
fixes from D11847.
r221876 was not reapplied alone because it was not safe and D11847 was not
applied alone because it needs r221876 to produce correct results.

This should fix PR24596.

Original commit message for r221876:
Let's try this again...

This reverts r219432, plus a bug fix.

Description of the bug in r219432 (by Nick):

The bug was using AllPositive to break out of the loop; if the loop break
condition i != e is changed to i != e && AllPositive then the
test_modulo_analysis_with_global test I've added will fail as the Modulo will
be calculated incorrectly (as the last loop iteration is skipped, so Modulo
isn't updated with its Scale).

Nick also adds this comment:

ComputeSignBit is safe to use in loops as it takes into account phi nodes, and
the  == EK_ZeroEx check is safe in loops as, no matter how the variable changes
between iterations, zero-extensions will always guarantee a zero sign bit. The
isValueEqualInPotentialCycles check is therefore definitely not needed as all
the variable analysis holds no matter how the variables change between loop
iterations.

And this patch also adds another enhancement to GetLinearExpression - basically
to convert ConstantInts to Offsets (see test_const_eval and
test_const_eval_scaled for the situations this improves).

Original commit message:

This reverts r218944, which reverted r218714, plus a bug fix.

Description of the bug in r218714 (by Nick):

The original patch forgot to check if the Scale in VariableGEPIndex flipped the
sign of the variable. The BasicAA pass iterates over the instructions in the
order they appear in the function, and so BasicAliasAnalysis::aliasGEP is
called with the variable it first comes across as parameter GEP1. Adding a
%reorder label puts the definition of %a after %b so aliasGEP is called with %b
as the first parameter and %a as the second. aliasGEP later calculates that %a
== %b + 1 - %idxprom where %idxprom >= 0 (if %a was passed as the first
parameter it would calculate %b == %a - 1 + %idxprom where %idxprom >= 0) -
ignoring that %idxprom is scaled by -1 here lead the patch to incorrectly
conclude that %a > %b.

Revised patch by Nick White, thanks! Thanks to Lang to isolating the bug.
Slightly modified by me to add an early exit from the loop and avoid
unnecessary, but expensive, function calls.

Original commit message:

Two related things:

1. Fixes a bug when calculating the offset in GetLinearExpression. The code
   previously used zext to extend the offset, so negative offsets were converted
   to large positive ones.

2. Enhance aliasGEP to deduce that, if the difference between two GEP
   allocations is positive and all the variables that govern the offset are also
   positive (i.e. the offset is strictly after the higher base pointer), then
   locations that fit in the gap between the two base pointers are NoAlias.

Patch by Nick White!

Message from D11847:
Un-revert of r241981 and fix for PR23626. The 'Or' case of GetLinearExpression
delegates to 'Add' if possible, and if not it returns an Opaque value.
Unfortunately the Scale and Offsets weren't being set (and so defaulted to 0) -
and a scale of zero effectively removes the variable from the GEP instruction.
This meant that BasicAA would return MustAliases when it should have been
returning PartialAliases (and PR23626 was an example of the GVN pass using an
incorrect MustAlias to merge loads from what should have been different
pointers).

Differential Revision: http://reviews.llvm.org/D11847
Patch by Nick White <n.j.white@gmail.com>!

llvm-svn: 246502
2015-08-31 22:32:47 +00:00
Quentin Colombet 861ad97e6f [BasicAA] Add a test for PR24468 to be sure we won't regress
when we finally get the GEP aliasing right.

llvm-svn: 245395
2015-08-19 00:08:26 +00:00
Quentin Colombet b700e357b5 [BasicAA] Revert r221876 because it can produce incorrect aliasing
information: see PR24468.

llvm-svn: 245394
2015-08-19 00:07:20 +00:00
Igor Laevsky 30143aee11 Emit argmemonly attribute for intrinsics.
Differential Revision: http://reviews.llvm.org/D11352

llvm-svn: 244920
2015-08-13 17:40:04 +00:00
Jonathan Roelofs 49e46ce8e2 Fix a bunch of trivial cases of 'CHECK[^:]*$' in the tests. NFCI
I looked into adding a warning / error for this to FileCheck, but there doesn't
seem to be a good way to avoid it triggering on the instances of it in RUN lines.

llvm-svn: 244481
2015-08-10 19:01:27 +00:00
Igor Laevsky 2ba8374612 NFC. Explicitly specify attributes in BasicAA/cs-cs.ll test.
This will simplify verifying correctness for a changes which modify attributes.

llvm-svn: 243016
2015-07-23 14:31:18 +00:00
Tobias Edler von Koch d8ce16b1e6 Analyze recursive PHI nodes in BasicAA
Summary:
This patch allows phi nodes like
  %x = phi [ %incptr, ... ] [ %var, ... ]
  %incptr = getelementptr %x, 1
to be analyzed by BasicAliasAnalysis.

In aliasPHI, we can detect incoming values that are recursive GEPs with a
constant offset. Instead of trying to analyze a recursive GEP (and failing), 
we now ignore it and instead set the size of the memory referenced by
the PHINode to UnknownSize. This represents all the possible memory
locations the pointer represented by the PHINode could be advanced to
by the GEP.

For now, this new behavior is turned off by default to allow debugging of
performance degradations seen with SPEC/x86 and Hexagon benchmarks.
The flag -basicaa-recphi turns it on.


Reviewers: hfinkel, sanjoy

Subscribers: tobiasvk_caf, sanjoy, llvm-commits

Differential Revision: http://reviews.llvm.org/D10368

llvm-svn: 242320
2015-07-15 19:32:22 +00:00
Manuel Klimek 779cf85a4f Revert r241981 "Revert "Revert r236894 "[BasicAA] Fix zext & sext handling"""
The repros from PR23626 still fail.

llvm-svn: 242025
2015-07-13 13:50:55 +00:00
Hal Finkel ef28aad9f4 Revert "Revert r236894 "[BasicAA] Fix zext & sext handling""
r236894 caused PR23626 (Clang miscompiles webkit's base64 decoder), and was
reverted in r237984. This reapplies the patch with an additional test case for
PR23626 and the associated fix (both scales and offsets in the
BasicAliasAnalysis::constantOffsetHeuristic should initially be zero).

Patch by Nick White, thanks!

llvm-svn: 241981
2015-07-11 11:04:54 +00:00
Igor Laevsky 39d662f7ba Add argmemonly attribute.
This change adds new attribute called "argmemonly". Function marked with this attribute can only access memory through it's argument pointers. This attribute directly corresponds to the "OnlyAccessesArgumentPointees" ModRef behaviour in alias analysis.

Differential Revision: http://reviews.llvm.org/D10398

llvm-svn: 241979
2015-07-11 10:30:36 +00:00
Hans Wennborg 2ecb8dc39c Revert r236894 "[BasicAA] Fix zext & sext handling"
This seems to have caused PR23626: Clang miscompiles webkit's base64 decoder

llvm-svn: 237984
2015-05-22 01:27:37 +00:00
Sanjoy Das 14f5080aa1 [BasicAA] Fix zext & sext handling
Summary:

There are several unhandled edge cases in BasicAA's GetLinearExpression
method. This changes fixes outstanding issues, including zext / sext of
a constant with the sign bit set, and the refusal to decompose zexts or
sexts of wrapping arithmetic.

Test Plan: Unit tests added in //q.ext.ll//.

Patch by Nick White.

Reviewers: hfinkel, sanjoy

Reviewed By: hfinkel, sanjoy

Subscribers: sanjoy, llvm-commits, hfinkel

Differential Revision: http://reviews.llvm.org/D6682

llvm-svn: 236894
2015-05-08 18:58:55 +00:00
David Blaikie 23af64846f [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 f72d05bc7b [opaque pointer type] Add textual IR support for explicit type parameter to gep operator
Similar to gep (r230786) and load (r230794) changes.

Similar migration script can be used to update test cases, which
successfully migrated all of LLVM and Polly, but about 4 test cases
needed manually changes in Clang.

(this script will read the contents of stdin and massage it into stdout
- wrap it in the 'apply.sh' script shown in previous commits + xargs to
apply it over a large set of test cases)

import fileinput
import sys
import re

rep = re.compile(r"(getelementptr(?:\s+inbounds)?\s*\()((<\d*\s+x\s+)?([^@]*?)(|\s*addrspace\(\d+\))\s*\*(?(3)>)\s*)(?=$|%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|zeroinitializer|<|\[\[[a-zA-Z]|\{\{)", re.MULTILINE | re.DOTALL)

def conv(match):
  line = match.group(1)
  line += match.group(4)
  line += ", "
  line += match.group(2)
  return line

line = sys.stdin.read()
off = 0
for match in re.finditer(rep, line):
  sys.stdout.write(line[off:match.start()])
  sys.stdout.write(conv(match))
  off = match.end()
sys.stdout.write(line[off:])

llvm-svn: 232184
2015-03-13 18:20:45 +00:00
David Blaikie a79ac14fa6 [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 79e6c74981 [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