summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
Diffstat
-rw-r--r--llvm/include/llvm/Analysis/AliasSetTracker.h16
-rw-r--r--llvm/lib/Analysis/AliasSetTracker.cpp35
-rw-r--r--llvm/test/Transforms/LICM/pr27262.ll33
3 files changed, 64 insertions, 20 deletions
diff --git a/llvm/include/llvm/Analysis/AliasSetTracker.h b/llvm/include/llvm/Analysis/AliasSetTracker.h
index 1a71dc501ca..760a7640ae2 100644
--- a/llvm/include/llvm/Analysis/AliasSetTracker.h
+++ b/llvm/include/llvm/Analysis/AliasSetTracker.h
@@ -59,8 +59,12 @@ class AliasSet : public ilist_node<AliasSet> {
return &NextInList;
}
- void updateSizeAndAAInfo(uint64_t NewSize, const AAMDNodes &NewAAInfo) {
- if (NewSize > Size) Size = NewSize;
+ bool updateSizeAndAAInfo(uint64_t NewSize, const AAMDNodes &NewAAInfo) {
+ bool SizeChanged = false;
+ if (NewSize > Size) {
+ Size = NewSize;
+ SizeChanged = true;
+ }
if (AAInfo == DenseMapInfo<AAMDNodes>::getEmptyKey())
// We don't have a AAInfo yet. Set it to NewAAInfo.
@@ -68,6 +72,8 @@ class AliasSet : public ilist_node<AliasSet> {
else if (AAInfo != NewAAInfo)
// NewAAInfo conflicts with AAInfo.
AAInfo = DenseMapInfo<AAMDNodes>::getTombstoneKey();
+
+ return SizeChanged;
}
uint64_t getSize() const { return Size; }
@@ -365,7 +371,7 @@ public:
/// otherwise return null.
AliasSet *getAliasSetForPointerIfExists(const Value *P, uint64_t Size,
const AAMDNodes &AAInfo) {
- return findAliasSetForPointer(P, Size, AAInfo);
+ return mergeAliasSetsForPointer(P, Size, AAInfo);
}
/// Return true if the specified location is represented by this alias set,
@@ -425,8 +431,8 @@ private:
AS.Access |= E;
return AS;
}
- AliasSet *findAliasSetForPointer(const Value *Ptr, uint64_t Size,
- const AAMDNodes &AAInfo);
+ AliasSet *mergeAliasSetsForPointer(const Value *Ptr, uint64_t Size,
+ const AAMDNodes &AAInfo);
AliasSet *findAliasSetForUnknownInst(Instruction *Inst);
};
diff --git a/llvm/lib/Analysis/AliasSetTracker.cpp b/llvm/lib/Analysis/AliasSetTracker.cpp
index 3cafb46f289..4cf7641dd77 100644
--- a/llvm/lib/Analysis/AliasSetTracker.cpp
+++ b/llvm/lib/Analysis/AliasSetTracker.cpp
@@ -208,13 +208,12 @@ void AliasSetTracker::clear() {
}
-/// findAliasSetForPointer - Given a pointer, find the one alias set to put the
-/// instruction referring to the pointer into. If there are multiple alias sets
-/// that may alias the pointer, merge them together and return the unified set.
-///
-AliasSet *AliasSetTracker::findAliasSetForPointer(const Value *Ptr,
- uint64_t Size,
- const AAMDNodes &AAInfo) {
+/// mergeAliasSetsForPointer - Given a pointer, merge all alias sets that may
+/// alias the pointer. Return the unified set, or nullptr if no set that aliases
+/// the pointer was found.
+AliasSet *AliasSetTracker::mergeAliasSetsForPointer(const Value *Ptr,
+ uint64_t Size,
+ const AAMDNodes &AAInfo) {
AliasSet *FoundSet = nullptr;
for (iterator I = begin(), E = end(); I != E;) {
iterator Cur = I++;
@@ -274,12 +273,18 @@ AliasSet &AliasSetTracker::getAliasSetForPointer(Value *Pointer, uint64_t Size,
// Check to see if the pointer is already known.
if (Entry.hasAliasSet()) {
- Entry.updateSizeAndAAInfo(Size, AAInfo);
+ // If the size changed, we may need to merge several alias sets.
+ // Note that we can *not* return the result of mergeAliasSetsForPointer
+ // due to a quirk of alias analysis behavior. Since alias(undef, undef)
+ // is NoAlias, mergeAliasSetsForPointer(undef, ...) will not find the
+ // the right set for undef, even if it exists.
+ if (Entry.updateSizeAndAAInfo(Size, AAInfo))
+ mergeAliasSetsForPointer(Pointer, Size, AAInfo);
// Return the set!
return *Entry.getAliasSet(*this)->getForwardedTarget(*this);
}
- if (AliasSet *AS = findAliasSetForPointer(Pointer, Size, AAInfo)) {
+ if (AliasSet *AS = mergeAliasSetsForPointer(Pointer, Size, AAInfo)) {
// Add it to the alias set it aliases.
AS->addPointer(*this, Entry, Size, AAInfo);
return *AS;
@@ -457,7 +462,7 @@ void AliasSetTracker::remove(AliasSet &AS) {
bool
AliasSetTracker::remove(Value *Ptr, uint64_t Size, const AAMDNodes &AAInfo) {
- AliasSet *AS = findAliasSetForPointer(Ptr, Size, AAInfo);
+ AliasSet *AS = mergeAliasSetsForPointer(Ptr, Size, AAInfo);
if (!AS) return false;
remove(*AS);
return true;
@@ -470,7 +475,7 @@ bool AliasSetTracker::remove(LoadInst *LI) {
AAMDNodes AAInfo;
LI->getAAMetadata(AAInfo);
- AliasSet *AS = findAliasSetForPointer(LI->getOperand(0), Size, AAInfo);
+ AliasSet *AS = mergeAliasSetsForPointer(LI->getOperand(0), Size, AAInfo);
if (!AS) return false;
remove(*AS);
return true;
@@ -483,7 +488,7 @@ bool AliasSetTracker::remove(StoreInst *SI) {
AAMDNodes AAInfo;
SI->getAAMetadata(AAInfo);
- AliasSet *AS = findAliasSetForPointer(SI->getOperand(1), Size, AAInfo);
+ AliasSet *AS = mergeAliasSetsForPointer(SI->getOperand(1), Size, AAInfo);
if (!AS) return false;
remove(*AS);
return true;
@@ -493,8 +498,8 @@ bool AliasSetTracker::remove(VAArgInst *VAAI) {
AAMDNodes AAInfo;
VAAI->getAAMetadata(AAInfo);
- AliasSet *AS = findAliasSetForPointer(VAAI->getOperand(0),
- MemoryLocation::UnknownSize, AAInfo);
+ AliasSet *AS = mergeAliasSetsForPointer(VAAI->getOperand(0),
+ MemoryLocation::UnknownSize, AAInfo);
if (!AS) return false;
remove(*AS);
return true;
@@ -510,7 +515,7 @@ bool AliasSetTracker::remove(MemSetInst *MSI) {
else
Len = MemoryLocation::UnknownSize;
- AliasSet *AS = findAliasSetForPointer(MSI->getRawDest(), Len, AAInfo);
+ AliasSet *AS = mergeAliasSetsForPointer(MSI->getRawDest(), Len, AAInfo);
if (!AS)
return false;
remove(*AS);
diff --git a/llvm/test/Transforms/LICM/pr27262.ll b/llvm/test/Transforms/LICM/pr27262.ll
new file mode 100644
index 00000000000..5fc6d9389e0
--- /dev/null
+++ b/llvm/test/Transforms/LICM/pr27262.ll
@@ -0,0 +1,33 @@
+; RUN: opt -S -basicaa -licm < %s | FileCheck %s
+
+target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32"
+target triple = "i686-pc-windows-msvc18.0.0"
+
+; Make sure the store to v is not sunk past the memset
+; CHECK-LABEL: @main
+; CHECK: for.body:
+; CHECK-NEXT: store i8 1, i8* %p
+; CHECK-NEXT: store i8 2, i8* %p1
+; CHECK-NEXT: call void @llvm.memset
+; CHECK: end:
+; CHECK-NEXT: ret i32 0
+
+define i32 @main(i1 %k, i8* %p) {
+entry:
+ %p1 = getelementptr i8, i8* %p, i32 1
+ br label %for.body
+
+for.body:
+ store i8 1, i8* %p, align 1
+ store i8 2, i8* %p1, align 1
+ call void @llvm.memset.p0i8.i32(i8* %p, i8 255, i32 4, i32 1, i1 false)
+ br label %for.latch
+
+for.latch:
+ br i1 %k, label %for.body, label %end
+
+end:
+ ret i32 0
+}
+
+declare void @llvm.memset.p0i8.i32(i8* nocapture, i8, i32, i32, i1)
OpenPOWER on IntegriCloud