[llvm-branch-commits] [llvm-branch] r206051 - Merging r198290:
Tom Stellard
thomas.stellard at amd.com
Fri Apr 11 12:35:37 PDT 2014
Author: tstellar
Date: Fri Apr 11 14:35:37 2014
New Revision: 206051
URL: http://llvm.org/viewvc/llvm-project?rev=206051&view=rev
Log:
Merging r198290:
------------------------------------------------------------------------
r198290 | aschwaighofer | 2014-01-01 22:31:36 -0500 (Wed, 01 Jan 2014) | 23 lines
BasicAA: Fix value equality and phi cycles
When there are cycles in the value graph we have to be careful interpreting
"Value*" identity as "value" equivalence. We interpret the value of a phi node
as the value of its operands.
When we check for value equivalence now we make sure that the "Value*" dominates
all cycles (phis).
%0 = phi [%noaliasval, %addr2]
%l = load %ptr
%addr1 = gep @a, 0, %l
%addr2 = gep @a, 0, (%l + 1)
store %ptr ...
Before this patch we would return NoAlias for (%0, %addr1) which is wrong
because the value of the load is from different iterations of the loop.
Tested on x86_64 -mavx at O3 and O3 -flto with no performance or compile time
regressions.
PR18068
radar://15653794
------------------------------------------------------------------------
Modified:
llvm/branches/release_34/lib/Analysis/BasicAliasAnalysis.cpp
llvm/branches/release_34/test/Analysis/BasicAA/2006-03-03-BadArraySubscript.ll
llvm/branches/release_34/test/Analysis/BasicAA/phi-aa.ll
llvm/branches/release_34/test/Analysis/BasicAA/phi-spec-order.ll
llvm/branches/release_34/test/Analysis/GlobalsModRef/aliastest.ll
llvm/branches/release_34/test/Transforms/ObjCARC/weak-copies.ll
llvm/branches/release_34/test/Transforms/ObjCARC/weak-dce.ll
llvm/branches/release_34/utils/release/test-release.sh
Modified: llvm/branches/release_34/lib/Analysis/BasicAliasAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_34/lib/Analysis/BasicAliasAnalysis.cpp?rev=206051&r1=206050&r2=206051&view=diff
==============================================================================
--- llvm/branches/release_34/lib/Analysis/BasicAliasAnalysis.cpp (original)
+++ llvm/branches/release_34/lib/Analysis/BasicAliasAnalysis.cpp Fri Apr 11 14:35:37 2014
@@ -18,6 +18,7 @@
#include "llvm/ADT/SmallVector.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/CaptureTracking.h"
+#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/Analysis/ValueTracking.h"
@@ -38,6 +39,12 @@
#include <algorithm>
using namespace llvm;
+/// Cutoff after which to stop analysing a set of phi nodes potentially involved
+/// in a cycle. Because we are analysing 'through' phi nodes we need to be
+/// careful with value equivalence. We use dominance to make sure a value cannot
+/// be involved in a cycle.
+const unsigned MaxNumPhiBBsValueDominanceCheck = 20;
+
//===----------------------------------------------------------------------===//
// Useful predicates
//===----------------------------------------------------------------------===//
@@ -403,42 +410,6 @@ DecomposeGEPExpression(const Value *V, i
return V;
}
-/// GetIndexDifference - Dest and Src are the variable indices from two
-/// decomposed GetElementPtr instructions GEP1 and GEP2 which have common base
-/// pointers. Subtract the GEP2 indices from GEP1 to find the symbolic
-/// difference between the two pointers.
-static void GetIndexDifference(SmallVectorImpl<VariableGEPIndex> &Dest,
- const SmallVectorImpl<VariableGEPIndex> &Src) {
- if (Src.empty()) return;
-
- for (unsigned i = 0, e = Src.size(); i != e; ++i) {
- const Value *V = Src[i].V;
- ExtensionKind Extension = Src[i].Extension;
- int64_t Scale = Src[i].Scale;
-
- // Find V in Dest. This is N^2, but pointer indices almost never have more
- // than a few variable indexes.
- for (unsigned j = 0, e = Dest.size(); j != e; ++j) {
- if (Dest[j].V != V || Dest[j].Extension != Extension) continue;
-
- // If we found it, subtract off Scale V's from the entry in Dest. If it
- // goes to zero, remove the entry.
- if (Dest[j].Scale != Scale)
- Dest[j].Scale -= Scale;
- else
- Dest.erase(Dest.begin()+j);
- Scale = 0;
- break;
- }
-
- // If we didn't consume this entry, add it to the end of the Dest list.
- if (Scale) {
- VariableGEPIndex Entry = { V, Extension, -Scale };
- Dest.push_back(Entry);
- }
- }
-}
-
//===----------------------------------------------------------------------===//
// BasicAliasAnalysis Pass
//===----------------------------------------------------------------------===//
@@ -482,6 +453,7 @@ namespace {
virtual AliasResult alias(const Location &LocA,
const Location &LocB) {
+ DT = 0;
assert(AliasCache.empty() && "AliasCache must be cleared after use!");
assert(notDifferentParent(LocA.Ptr, LocB.Ptr) &&
"BasicAliasAnalysis doesn't support interprocedural queries.");
@@ -492,6 +464,7 @@ namespace {
// SmallDenseMap if it ever grows larger.
// FIXME: This should really be shrink_to_inline_capacity_and_clear().
AliasCache.shrink_and_clear();
+ VisitedPhiBBs.clear();
return Alias;
}
@@ -532,9 +505,41 @@ namespace {
typedef SmallDenseMap<LocPair, AliasResult, 8> AliasCacheTy;
AliasCacheTy AliasCache;
+ /// \brief Track phi nodes we have visited. When interpret "Value" pointer
+ /// equality as value equality we need to make sure that the "Value" is not
+ /// part of a cycle. Otherwise, two uses could come from different
+ /// "iterations" of a cycle and see different values for the same "Value"
+ /// pointer.
+ /// The following example shows the problem:
+ /// %p = phi(%alloca1, %addr2)
+ /// %l = load %ptr
+ /// %addr1 = gep, %alloca2, 0, %l
+ /// %addr2 = gep %alloca2, 0, (%l + 1)
+ /// alias(%p, %addr1) -> MayAlias !
+ /// store %l, ...
+ SmallPtrSet<const BasicBlock*, 8> VisitedPhiBBs;
+
// Visited - Track instructions visited by pointsToConstantMemory.
SmallPtrSet<const Value*, 16> Visited;
+ // We use the dominator tree to check values can't be part of a cycle.
+ DominatorTree *DT;
+
+ /// \brief Check whether two Values can be considered equivalent.
+ ///
+ /// In addition to pointer equivalence of \p V1 and \p V2 this checks
+ /// whether they can not be part of a cycle in the value graph by looking at
+ /// all visited phi nodes an making sure that the value dominates all of
+ /// them.
+ bool isValueEqual(const Value *V1, const Value *V2);
+
+ /// \brief Dest and Src are the variable indices from two decomposed
+ /// GetElementPtr instructions GEP1 and GEP2 which have common base
+ /// pointers. Subtract the GEP2 indices from GEP1 to find the symbolic
+ /// difference between the two pointers.
+ void GetIndexDifference(SmallVectorImpl<VariableGEPIndex> &Dest,
+ const SmallVectorImpl<VariableGEPIndex> &Src);
+
// aliasGEP - Provide a bunch of ad-hoc rules to disambiguate a GEP
// instruction against another.
AliasResult aliasGEP(const GEPOperator *V1, uint64_t V1Size,
@@ -1094,6 +1099,10 @@ BasicAliasAnalysis::aliasPHI(const PHINo
const MDNode *PNTBAAInfo,
const Value *V2, uint64_t V2Size,
const MDNode *V2TBAAInfo) {
+ // Track phi nodes we have visited. We use this information when we determine
+ // value equivalence.
+ VisitedPhiBBs.insert(PN->getParent());
+
// If the values are PHIs in the same block, we can do a more precise
// as well as efficient check: just check for aliases between the values
// on corresponding edges.
@@ -1187,7 +1196,7 @@ BasicAliasAnalysis::aliasCheck(const Val
V2 = V2->stripPointerCasts();
// Are we checking for alias of the same value?
- if (V1 == V2) return MustAlias;
+ if (isValueEqual(V1, V2)) return MustAlias;
if (!V1->getType()->isPointerTy() || !V2->getType()->isPointerTy())
return NoAlias; // Scalars cannot alias each other
@@ -1307,3 +1316,69 @@ BasicAliasAnalysis::aliasCheck(const Val
Location(V2, V2Size, V2TBAAInfo));
return AliasCache[Locs] = Result;
}
+
+bool BasicAliasAnalysis::isValueEqual(const Value *V, const Value *V2) {
+ if (V != V2)
+ return false;
+
+ const Instruction *Inst = dyn_cast<Instruction>(V);
+ if (!Inst)
+ return true;
+
+ // Use the dominance if available.
+ DT = getAnalysisIfAvailable<DominatorTree>();
+ if (DT) {
+ if (VisitedPhiBBs.size() > MaxNumPhiBBsValueDominanceCheck)
+ return false;
+
+ // Make sure that the visited phis are dominated by the Value.
+ for (SmallPtrSet<const BasicBlock *, 8>::iterator
+ PI = VisitedPhiBBs.begin(),
+ PE = VisitedPhiBBs.end();
+ PI != PE; ++PI)
+ if (!DT->dominates(Inst, *PI))
+ return false;
+ return true;
+ }
+
+ return false;
+}
+
+/// GetIndexDifference - Dest and Src are the variable indices from two
+/// decomposed GetElementPtr instructions GEP1 and GEP2 which have common base
+/// pointers. Subtract the GEP2 indices from GEP1 to find the symbolic
+/// difference between the two pointers.
+void BasicAliasAnalysis::GetIndexDifference(
+ SmallVectorImpl<VariableGEPIndex> &Dest,
+ const SmallVectorImpl<VariableGEPIndex> &Src) {
+ if (Src.empty())
+ return;
+
+ for (unsigned i = 0, e = Src.size(); i != e; ++i) {
+ const Value *V = Src[i].V;
+ ExtensionKind Extension = Src[i].Extension;
+ int64_t Scale = Src[i].Scale;
+
+ // Find V in Dest. This is N^2, but pointer indices almost never have more
+ // than a few variable indexes.
+ for (unsigned j = 0, e = Dest.size(); j != e; ++j) {
+ if (!isValueEqual(Dest[j].V, V) || Dest[j].Extension != Extension)
+ continue;
+
+ // If we found it, subtract off Scale V's from the entry in Dest. If it
+ // goes to zero, remove the entry.
+ if (Dest[j].Scale != Scale)
+ Dest[j].Scale -= Scale;
+ else
+ Dest.erase(Dest.begin() + j);
+ Scale = 0;
+ break;
+ }
+
+ // If we didn't consume this entry, add it to the end of the Dest list.
+ if (Scale) {
+ VariableGEPIndex Entry = { V, Extension, -Scale };
+ Dest.push_back(Entry);
+ }
+ }
+}
Modified: llvm/branches/release_34/test/Analysis/BasicAA/2006-03-03-BadArraySubscript.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_34/test/Analysis/BasicAA/2006-03-03-BadArraySubscript.ll?rev=206051&r1=206050&r2=206051&view=diff
==============================================================================
--- llvm/branches/release_34/test/Analysis/BasicAA/2006-03-03-BadArraySubscript.ll (original)
+++ llvm/branches/release_34/test/Analysis/BasicAA/2006-03-03-BadArraySubscript.ll Fri Apr 11 14:35:37 2014
@@ -1,4 +1,4 @@
-; RUN: opt < %s -basicaa -aa-eval -disable-output 2>&1 | FileCheck %s
+; RUN: opt < %s -domtree -basicaa -aa-eval -disable-output 2>&1 | FileCheck %s
; TEST that A[1][0] may alias A[0][i].
target datalayout = "E-p:64:64:64-a0:0:8-f32:32:32-f64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-v64:64:64-v128:128:128"
Modified: llvm/branches/release_34/test/Analysis/BasicAA/phi-aa.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_34/test/Analysis/BasicAA/phi-aa.ll?rev=206051&r1=206050&r2=206051&view=diff
==============================================================================
--- llvm/branches/release_34/test/Analysis/BasicAA/phi-aa.ll (original)
+++ llvm/branches/release_34/test/Analysis/BasicAA/phi-aa.ll Fri Apr 11 14:35:37 2014
@@ -1,12 +1,20 @@
; RUN: opt < %s -basicaa -aa-eval -print-all-alias-modref-info -disable-output 2>&1 | FileCheck %s
+; RUN: opt < %s -domtree -basicaa -aa-eval -print-all-alias-modref-info -disable-output 2>&1 | FileCheck %s --check-prefix=DOM
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
; rdar://7282591
@X = common global i32 0
@Y = common global i32 0
@Z = common global i32 0
+; CHECK-LABEL: foo
; CHECK: NoAlias: i32* %P, i32* @Z
+; DOM-LABEL: foo
+; DOM: NoAlias: i32* %P, i32* @Z
+
define void @foo(i32 %cond) nounwind {
entry:
%"alloca point" = bitcast i32 0 to i32
@@ -29,3 +37,49 @@ bb2:
return:
ret void
}
+
+; Pointers can vary in between iterations of loops.
+; PR18068
+
+; CHECK-LABEL: pr18068
+; CHECK: MayAlias: i32* %0, i32* %arrayidx5
+
+; DOM-LABEL: pr18068
+; DOM: MayAlias: i32* %0, i32* %arrayidx5
+
+define i32 @pr18068(i32* %jj7, i32* %j) {
+entry:
+ %oa5 = alloca [100 x i32], align 16
+ br label %codeRepl
+
+codeRepl:
+ %0 = phi i32* [ %arrayidx13, %for.body ], [ %j, %entry ]
+ %targetBlock = call i1 @cond(i32* %jj7)
+ br i1 %targetBlock, label %for.body, label %bye
+
+for.body:
+ %1 = load i32* %jj7, align 4
+ %idxprom4 = zext i32 %1 to i64
+ %arrayidx5 = getelementptr inbounds [100 x i32]* %oa5, i64 0, i64 %idxprom4
+ %2 = load i32* %arrayidx5, align 4
+ %sub6 = sub i32 %2, 6
+ store i32 %sub6, i32* %arrayidx5, align 4
+ ; %0 and %arrayidx5 can alias! It is not safe to DSE the above store.
+ %3 = load i32* %0, align 4
+ store i32 %3, i32* %arrayidx5, align 4
+ %sub11 = add i32 %1, -1
+ %idxprom12 = zext i32 %sub11 to i64
+ %arrayidx13 = getelementptr inbounds [100 x i32]* %oa5, i64 0, i64 %idxprom12
+ call void @inc(i32* %jj7)
+ br label %codeRepl
+
+bye:
+ %.reload = load i32* %jj7, align 4
+ ret i32 %.reload
+}
+
+declare i1 @cond(i32*)
+
+declare void @inc(i32*)
+
+
Modified: llvm/branches/release_34/test/Analysis/BasicAA/phi-spec-order.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_34/test/Analysis/BasicAA/phi-spec-order.ll?rev=206051&r1=206050&r2=206051&view=diff
==============================================================================
--- llvm/branches/release_34/test/Analysis/BasicAA/phi-spec-order.ll (original)
+++ llvm/branches/release_34/test/Analysis/BasicAA/phi-spec-order.ll Fri Apr 11 14:35:37 2014
@@ -1,6 +1,6 @@
target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-f128:128:128-v128:128:128-n32:64"
target triple = "powerpc64-bgq-linux"
-; RUN: opt < %s -basicaa -aa-eval -print-all-alias-modref-info -disable-output 2>&1 | FileCheck %s
+; RUN: opt < %s -domtree -basicaa -aa-eval -print-all-alias-modref-info -disable-output 2>&1 | FileCheck %s
@X = external global [16000 x double], align 32
@Y = external global [16000 x double], align 32
Modified: llvm/branches/release_34/test/Analysis/GlobalsModRef/aliastest.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_34/test/Analysis/GlobalsModRef/aliastest.ll?rev=206051&r1=206050&r2=206051&view=diff
==============================================================================
--- llvm/branches/release_34/test/Analysis/GlobalsModRef/aliastest.ll (original)
+++ llvm/branches/release_34/test/Analysis/GlobalsModRef/aliastest.ll Fri Apr 11 14:35:37 2014
@@ -1,4 +1,4 @@
-; RUN: opt < %s -basicaa -globalsmodref-aa -gvn -S | FileCheck %s
+; RUN: opt < %s -domtree -basicaa -globalsmodref-aa -gvn -S | FileCheck %s
@X = internal global i32 4 ; <i32*> [#uses=1]
Modified: llvm/branches/release_34/test/Transforms/ObjCARC/weak-copies.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_34/test/Transforms/ObjCARC/weak-copies.ll?rev=206051&r1=206050&r2=206051&view=diff
==============================================================================
--- llvm/branches/release_34/test/Transforms/ObjCARC/weak-copies.ll (original)
+++ llvm/branches/release_34/test/Transforms/ObjCARC/weak-copies.ll Fri Apr 11 14:35:37 2014
@@ -1,4 +1,4 @@
-; RUN: opt -S -basicaa -objc-arc < %s | FileCheck %s
+; RUN: opt -S -domtree -basicaa -objc-arc < %s | FileCheck %s
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
target triple = "x86_64-apple-darwin11.0.0"
Modified: llvm/branches/release_34/test/Transforms/ObjCARC/weak-dce.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_34/test/Transforms/ObjCARC/weak-dce.ll?rev=206051&r1=206050&r2=206051&view=diff
==============================================================================
--- llvm/branches/release_34/test/Transforms/ObjCARC/weak-dce.ll (original)
+++ llvm/branches/release_34/test/Transforms/ObjCARC/weak-dce.ll Fri Apr 11 14:35:37 2014
@@ -1,4 +1,4 @@
-; RUN: opt -S -basicaa -objc-arc < %s | FileCheck %s
+; RUN: opt -S -domtree -basicaa -objc-arc < %s | FileCheck %s
; rdar://11434915
; Delete the weak calls and replace them with just the net retain.
Modified: llvm/branches/release_34/utils/release/test-release.sh
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_34/utils/release/test-release.sh?rev=206051&r1=206050&r2=206051&view=diff
==============================================================================
--- llvm/branches/release_34/utils/release/test-release.sh (original)
+++ llvm/branches/release_34/utils/release/test-release.sh Fri Apr 11 14:35:37 2014
@@ -26,6 +26,7 @@ Base_url="http://llvm.org/svn/llvm-proje
Release=""
Release_no_dot=""
RC=""
+DOT=""
Triple=""
use_gzip="no"
do_checkout="yes"
@@ -45,6 +46,7 @@ function usage() {
echo ""
echo " -release X.Y The release number to test."
echo " -rc NUM The pre-release candidate number."
+ echo " -dot NUM The dot release to test e.g. X.Y.DOT_NUM [default: 0]"
echo " -final The final release candidate."
echo " -triple TRIPLE The target triple for this machine."
echo " -j NUM Number of compile jobs to run. [default: 3]"
@@ -76,6 +78,13 @@ while [ $# -gt 0 ]; do
-final | --final )
RC=final
;;
+ -dot | --dot )
+ shift
+ DOT="$1"
+ if [ $DOT -eq 0 ]; then
+ DOT=""
+ fi
+ ;;
-triple | --triple )
shift
Triple="$1"
@@ -137,6 +146,10 @@ while [ $# -gt 0 ]; do
shift
done
+if [ -n "$DOT" ]; then
+ Release="$Release.$DOT"
+fi
+
# Check required arguments.
if [ -z "$Release" ]; then
echo "error: no release number specified"
@@ -217,12 +230,29 @@ if [ `uname -s` != "Darwin" ]; then
check_program_exists 'objdump'
fi
+function get_svn_tag() {
+ case $1 in
+ # llvm and clang are the only projects currently doing dot releases.
+ llvm | cfe)
+ if [ -z $DOT ]; then
+ SvnTag="$RC"
+ else
+ SvnTag="dot$DOT-$RC"
+ fi
+ ;;
+ *)
+ SvnTag="$RC"
+ ;;
+ esac
+}
+
# Make sure that the URLs are valid.
function check_valid_urls() {
for proj in $projects ; do
echo "# Validating $proj SVN URL"
- if ! svn ls $Base_url/$proj/tags/RELEASE_$Release_no_dot/$RC > /dev/null 2>&1 ; then
+ get_svn_tag "$proj"
+ if ! svn ls $Base_url/$proj/tags/RELEASE_$Release_no_dot/$SvnTag > /dev/null 2>&1 ; then
echo "llvm $Release release candidate $RC doesn't exist!"
exit 1
fi
@@ -235,7 +265,8 @@ function export_sources() {
for proj in $projects ; do
echo "# Exporting $proj $Release-RC$RC sources"
- if ! svn export -q $Base_url/$proj/tags/RELEASE_$Release_no_dot/$RC $proj.src ; then
+ get_svn_tag "$proj"
+ if ! svn export -q $Base_url/$proj/tags/RELEASE_$Release_no_dot/$SvnTag $proj.src ; then
echo "error: failed to export $proj project"
exit 1
fi
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