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[MemCpyOpt] Use EarliestEscapeInfo #110280

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Merged
merged 2 commits into from
Sep 30, 2024
Merged

[MemCpyOpt] Use EarliestEscapeInfo #110280

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9736bcf
[MemCpyOpt] Use EarliestEscapeInfo
nikic Sep 27, 2024
f398017
Use eraseInstruction()
nikic Sep 28, 2024
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2 changes: 2 additions & 0 deletions llvm/include/llvm/Transforms/Scalar/MemCpyOptimizer.h
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Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,7 @@ class AssumptionCache;
class CallBase;
class CallInst;
class DominatorTree;
class EarliestEscapeInfo;
class Function;
class Instruction;
class LoadInst;
Expand All @@ -48,6 +49,7 @@ class MemCpyOptPass : public PassInfoMixin<MemCpyOptPass> {
PostDominatorTree *PDT = nullptr;
MemorySSA *MSSA = nullptr;
MemorySSAUpdater *MSSAU = nullptr;
EarliestEscapeInfo *EEI = nullptr;

public:
MemCpyOptPass() = default;
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15 changes: 9 additions & 6 deletions llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
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Expand Up @@ -284,6 +284,7 @@ static bool mayBeVisibleThroughUnwinding(Value *V, Instruction *Start,

void MemCpyOptPass::eraseInstruction(Instruction *I) {
MSSAU->removeMemoryAccess(I);
EEI->removeInstruction(I);
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Should we call MemCpyOptPass::eraseInstruction in

llvm-project/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp

Line 1157 in a94060c

NewCopySource->eraseFromParent();
? NewCopySource may be deleted after a BAA query.

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Nice catch, fixed!

I->eraseFromParent();
}

Expand Down Expand Up @@ -638,7 +639,7 @@ bool MemCpyOptPass::processStoreOfLoad(StoreInst *SI, LoadInst *LI,
if (!LI->isSimple() || !LI->hasOneUse() || LI->getParent() != SI->getParent())
return false;

BatchAAResults BAA(*AA);
BatchAAResults BAA(*AA, EEI);
auto *T = LI->getType();
// Don't introduce calls to memcpy/memmove intrinsics out of thin air if
// the corresponding libcalls are not available.
Expand Down Expand Up @@ -1147,14 +1148,14 @@ bool MemCpyOptPass::processMemCpyMemCpyDependence(MemCpyInst *M,
IRBuilder<> Builder(M);
auto *CopySource = MDep->getSource();
Instruction *NewCopySource = nullptr;
auto CleanupOnRet = llvm::make_scope_exit([&NewCopySource] {
auto CleanupOnRet = llvm::make_scope_exit([&] {
if (NewCopySource && NewCopySource->use_empty())
// Safety: It's safe here because we will only allocate more instructions
// after finishing all BatchAA queries, but we have to be careful if we
// want to do something like this in another place. Then we'd probably
// have to delay instruction removal until all transforms on an
// instruction finished.
NewCopySource->eraseFromParent();
eraseInstruction(NewCopySource);
});
MaybeAlign CopySourceAlign = MDep->getSourceAlign();
// We just need to calculate the actual size of the copy.
Expand Down Expand Up @@ -1751,7 +1752,7 @@ bool MemCpyOptPass::processMemCpy(MemCpyInst *M, BasicBlock::iterator &BBI) {
return true;
}

BatchAAResults BAA(*AA);
BatchAAResults BAA(*AA, EEI);
// FIXME: Not using getClobberingMemoryAccess() here due to PR54682.
MemoryAccess *AnyClobber = MA->getDefiningAccess();
MemoryLocation DestLoc = MemoryLocation::getForDest(M);
Expand Down Expand Up @@ -1876,7 +1877,7 @@ bool MemCpyOptPass::processByValArgument(CallBase &CB, unsigned ArgNo) {
if (!CallAccess)
return false;
MemCpyInst *MDep = nullptr;
BatchAAResults BAA(*AA);
BatchAAResults BAA(*AA, EEI);
MemoryAccess *Clobber = MSSA->getWalker()->getClobberingMemoryAccess(
CallAccess->getDefiningAccess(), Loc, BAA);
if (auto *MD = dyn_cast<MemoryDef>(Clobber))
Expand Down Expand Up @@ -1949,7 +1950,7 @@ bool MemCpyOptPass::processByValArgument(CallBase &CB, unsigned ArgNo) {
/// 4. The memcpy src is not modified during the call. (ModRef check shows no
/// Mod.)
bool MemCpyOptPass::processImmutArgument(CallBase &CB, unsigned ArgNo) {
BatchAAResults BAA(*AA);
BatchAAResults BAA(*AA, EEI);
Value *ImmutArg = CB.getArgOperand(ArgNo);

// 1. Ensure passed argument is immutable during call.
Expand Down Expand Up @@ -2117,6 +2118,8 @@ bool MemCpyOptPass::runImpl(Function &F, TargetLibraryInfo *TLI_,
MSSA = MSSA_;
MemorySSAUpdater MSSAU_(MSSA_);
MSSAU = &MSSAU_;
EarliestEscapeInfo EEI_(*DT);
EEI = &EEI_;

while (true) {
if (!iterateOnFunction(F))
Expand Down
14 changes: 4 additions & 10 deletions llvm/test/Transforms/MemCpyOpt/memcpy.ll
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Expand Up @@ -837,7 +837,7 @@ define void @memcpy_memcpy_escape_after1(ptr noalias %P, ptr noalias %Q) {
; CHECK-NEXT: [[MEMTMP:%.*]] = alloca [32 x i8], align 16
; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 16 [[MEMTMP]], ptr align 16 [[P:%.*]], i32 32, i1 false)
; CHECK-NEXT: call void @do_something()
; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 16 [[Q:%.*]], ptr align 16 [[MEMTMP]], i32 32, i1 false)
; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 16 [[Q:%.*]], ptr align 16 [[P]], i32 32, i1 false)
; CHECK-NEXT: call void @capture(ptr [[MEMTMP]])
; CHECK-NEXT: ret void
;
Expand All @@ -851,10 +851,8 @@ define void @memcpy_memcpy_escape_after1(ptr noalias %P, ptr noalias %Q) {

define void @memcpy_memcpy_escape_after2(ptr noalias %P, ptr noalias %Q) {
; CHECK-LABEL: @memcpy_memcpy_escape_after2(
; CHECK-NEXT: [[MEMTMP:%.*]] = alloca [32 x i8], align 16
; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 16 [[MEMTMP]], ptr align 16 [[P:%.*]], i32 32, i1 false)
; CHECK-NEXT: call void @do_something()
; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 16 [[Q:%.*]], ptr align 16 [[MEMTMP]], i32 32, i1 false)
; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 16 [[Q:%.*]], ptr align 16 [[P:%.*]], i32 32, i1 false)
; CHECK-NEXT: call void @capture(ptr [[P]])
; CHECK-NEXT: ret void
;
Expand All @@ -868,10 +866,8 @@ define void @memcpy_memcpy_escape_after2(ptr noalias %P, ptr noalias %Q) {

define void @memcpy_byval_escape_after(ptr noalias %P) {
; CHECK-LABEL: @memcpy_byval_escape_after(
; CHECK-NEXT: [[A:%.*]] = alloca [8 x i8], align 1
; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr align 4 [[A]], ptr align 4 [[P:%.*]], i64 8, i1 false)
; CHECK-NEXT: call void @do_something()
; CHECK-NEXT: call void @test4a(ptr byval(i8) align 1 [[A]])
; CHECK-NEXT: call void @test4a(ptr byval(i8) align 1 [[P:%.*]])
; CHECK-NEXT: call void @capture(ptr [[P]])
; CHECK-NEXT: ret void
;
Expand All @@ -885,10 +881,8 @@ define void @memcpy_byval_escape_after(ptr noalias %P) {

define void @memcpy_immut_escape_after(ptr align 4 noalias %val) {
; CHECK-LABEL: @memcpy_immut_escape_after(
; CHECK-NEXT: [[VAL1:%.*]] = alloca i8, align 4
; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr align 4 [[VAL1]], ptr align 4 [[VAL:%.*]], i64 1, i1 false)
; CHECK-NEXT: call void @do_something()
; CHECK-NEXT: call void @f(ptr noalias nocapture readonly align 4 [[VAL1]])
; CHECK-NEXT: call void @f(ptr noalias nocapture readonly align 4 [[VAL:%.*]])
; CHECK-NEXT: call void @capture(ptr [[VAL]])
; CHECK-NEXT: ret void
;
Expand Down
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