From 3be58ceecd37ded71d54087a062af273f9d0c342 Mon Sep 17 00:00:00 2001 From: Teresa Johnson Date: Wed, 28 Jun 2017 13:07:37 +0000 Subject: [PATCH] Add zero-length check to memcpy/memset load store loop expansion Summary: I was testing using this expansion logic in other cases besides NVPTX, and found some runtime failures due to the lack of a check for a zero length memcpy/memset before the loop. There is already such a check in the memmove expansion code though. Reviewers: hfinkel Subscribers: jholewinski, wdng, llvm-commits Differential Revision: https://reviews.llvm.org/D34707 llvm-svn: 306541 --- lib/Transforms/Utils/LowerMemIntrinsics.cpp | 17 ++++++++++++----- test/CodeGen/NVPTX/lower-aggr-copies.ll | 4 ++++ 2 files changed, 16 insertions(+), 5 deletions(-) diff --git a/lib/Transforms/Utils/LowerMemIntrinsics.cpp b/lib/Transforms/Utils/LowerMemIntrinsics.cpp index 0a51f9a0e4a..ef829d43b7d 100644 --- a/lib/Transforms/Utils/LowerMemIntrinsics.cpp +++ b/lib/Transforms/Utils/LowerMemIntrinsics.cpp @@ -27,8 +27,11 @@ void llvm::createMemCpyLoop(Instruction *InsertBefore, BasicBlock *LoopBB = BasicBlock::Create(F->getContext(), "loadstoreloop", F, NewBB); - OrigBB->getTerminator()->setSuccessor(0, LoopBB); IRBuilder<> Builder(OrigBB->getTerminator()); + Builder.CreateCondBr( + Builder.CreateICmpEQ(ConstantInt::get(TypeOfCopyLen, 0), CopyLen), NewBB, + LoopBB); + OrigBB->getTerminator()->eraseFromParent(); // SrcAddr and DstAddr are expected to be pointer types, // so no check is made here. @@ -167,6 +170,7 @@ static void createMemMoveLoop(Instruction *InsertBefore, static void createMemSetLoop(Instruction *InsertBefore, Value *DstAddr, Value *CopyLen, Value *SetValue, unsigned Align, bool IsVolatile) { + Type *TypeOfCopyLen = CopyLen->getType(); BasicBlock *OrigBB = InsertBefore->getParent(); Function *F = OrigBB->getParent(); BasicBlock *NewBB = @@ -174,8 +178,11 @@ static void createMemSetLoop(Instruction *InsertBefore, BasicBlock *LoopBB = BasicBlock::Create(F->getContext(), "loadstoreloop", F, NewBB); - OrigBB->getTerminator()->setSuccessor(0, LoopBB); IRBuilder<> Builder(OrigBB->getTerminator()); + Builder.CreateCondBr( + Builder.CreateICmpEQ(ConstantInt::get(TypeOfCopyLen, 0), CopyLen), NewBB, + LoopBB); + OrigBB->getTerminator()->eraseFromParent(); // Cast pointer to the type of value getting stored unsigned dstAS = cast(DstAddr->getType())->getAddressSpace(); @@ -183,8 +190,8 @@ static void createMemSetLoop(Instruction *InsertBefore, PointerType::get(SetValue->getType(), dstAS)); IRBuilder<> LoopBuilder(LoopBB); - PHINode *LoopIndex = LoopBuilder.CreatePHI(CopyLen->getType(), 0); - LoopIndex->addIncoming(ConstantInt::get(CopyLen->getType(), 0), OrigBB); + PHINode *LoopIndex = LoopBuilder.CreatePHI(TypeOfCopyLen, 0); + LoopIndex->addIncoming(ConstantInt::get(TypeOfCopyLen, 0), OrigBB); LoopBuilder.CreateStore( SetValue, @@ -192,7 +199,7 @@ static void createMemSetLoop(Instruction *InsertBefore, IsVolatile); Value *NewIndex = - LoopBuilder.CreateAdd(LoopIndex, ConstantInt::get(CopyLen->getType(), 1)); + LoopBuilder.CreateAdd(LoopIndex, ConstantInt::get(TypeOfCopyLen, 1)); LoopIndex->addIncoming(NewIndex, LoopBB); LoopBuilder.CreateCondBr(LoopBuilder.CreateICmpULT(NewIndex, CopyLen), LoopBB, diff --git a/test/CodeGen/NVPTX/lower-aggr-copies.ll b/test/CodeGen/NVPTX/lower-aggr-copies.ll index 192d4becb05..f522c6722ee 100644 --- a/test/CodeGen/NVPTX/lower-aggr-copies.ll +++ b/test/CodeGen/NVPTX/lower-aggr-copies.ll @@ -17,6 +17,8 @@ entry: ret i8* %dst ; IR-LABEL: @memcpy_caller +; IR: [[CMPREG:%[0-9]+]] = icmp eq i64 0, %n +; IR: br i1 [[CMPREG]], label %split, label %loadstoreloop ; IR: loadstoreloop: ; IR: [[LOADPTR:%[0-9]+]] = getelementptr inbounds i8, i8* %src, i64 ; IR-NEXT: [[VAL:%[0-9]+]] = load i8, i8* [[LOADPTR]] @@ -73,6 +75,8 @@ entry: ; IR-LABEL: @memset_caller ; IR: [[VAL:%[0-9]+]] = trunc i32 %c to i8 +; IR: [[CMPREG:%[0-9]+]] = icmp eq i64 0, %n +; IR: br i1 [[CMPREG]], label %split, label %loadstoreloop ; IR: loadstoreloop: ; IR: [[STOREPTR:%[0-9]+]] = getelementptr inbounds i8, i8* %dst, i64 ; IR-NEXT: store i8 [[VAL]], i8* [[STOREPTR]]