diff --git a/lib/Transforms/Scalar/DeadStoreElimination.cpp b/lib/Transforms/Scalar/DeadStoreElimination.cpp index 9f6a9533adf..c8c53606015 100644 --- a/lib/Transforms/Scalar/DeadStoreElimination.cpp +++ b/lib/Transforms/Scalar/DeadStoreElimination.cpp @@ -259,13 +259,6 @@ static bool isShortenable(Instruction *I) { } } - -/// isMemset - Returns true if this instruction is an intrinsic memset -static bool isMemset(Instruction *I) { - IntrinsicInst *II = dyn_cast(I); - return II && II->getIntrinsicID() == Intrinsic::memset; -} - /// getStoredPointerOperand - Return the pointer that is being written to. static Value *getStoredPointerOperand(Instruction *I) { if (StoreInst *SI = dyn_cast(I)) @@ -317,17 +310,14 @@ namespace { { OverwriteComplete, OverwriteEnd, - OverwriteStart, OverwriteUnknown }; } /// isOverwrite - Return 'OverwriteComplete' if a store to the 'Later' location /// completely overwrites a store to the 'Earlier' location. -/// 'OverwriteEnd' if the end of the 'Earlier' location is completely -/// overwritten by 'Later', 'OverWriteStart' if the start of 'Earlier' -/// is completely overwritten by 'Later' or 'OverwriteUnknown' if nothing -/// can be determined +/// 'OverwriteEnd' if the end of the 'Earlier' location is completely +/// overwritten by 'Later', or 'OverwriteUnknown' if nothing can be determined static OverwriteResult isOverwrite(const AliasAnalysis::Location &Later, const AliasAnalysis::Location &Earlier, AliasAnalysis &AA, @@ -428,21 +418,6 @@ static OverwriteResult isOverwrite(const AliasAnalysis::Location &Later, LaterOff < int64_t(EarlierOff + Earlier.Size) && int64_t(LaterOff + Later.Size) >= int64_t(EarlierOff + Earlier.Size)) return OverwriteEnd; - - // The other interesting case is if the later store overwrites the end of - // the earlier store - // - // |--earlier--| - // |-- later --| - // - // In this case we may want to trim the size of earlier to avoid generating - // writes to addresses which will definitely be overwritten later - if (EarlierOff >= LaterOff && - EarlierOff < int64_t(LaterOff + Later.Size) && - int64_t(EarlierOff + Earlier.Size) >= int64_t(LaterOff + Later.Size)) { - LaterOff = LaterOff + Later.Size; - return OverwriteStart; - } // Otherwise, they don't completely overlap. return OverwriteUnknown; @@ -614,45 +589,6 @@ bool DSE::runOnBasicBlock(BasicBlock &BB) { DepIntrinsic->setLength(TrimmedLength); MadeChange = true; } - } else if (OR == OverwriteStart && isMemset(DepWrite)) { - // TODO: base this on the target vector size so that if the earlier - // store was too small to get vector writes anyway then its likely - // a good idea to shorten it - // Power of 2 vector writes are probably always a bad idea to optimize - // as any store/memset/memcpy is likely using vector instructions so - // shortening it to not vector size is likely to be slower - // TODO: shorten memcpy and memmove by offsetting the source address. - MemIntrinsic* DepIntrinsic = cast(DepWrite); - unsigned DepWriteAlign = DepIntrinsic->getAlignment(); - if (llvm::isPowerOf2_64(InstWriteOffset) || - ((DepWriteAlign != 0) && InstWriteOffset % DepWriteAlign == 0)) { - - DEBUG(dbgs() << "DSE: Remove Dead Store:\n OW START: " - << *DepWrite << "\n KILLER (offset " - << InstWriteOffset << ", " - << DepWriteOffset << ", " - << DepLoc.Size << ")" - << *Inst << '\n'); - - Value* DepWriteLength = DepIntrinsic->getLength(); - Value* TrimmedLength = ConstantInt::get(DepWriteLength->getType(), - DepLoc.Size - - (InstWriteOffset - - DepWriteOffset)); - DepIntrinsic->setLength(TrimmedLength); - const TargetData *TD = AA->getTargetData(); - Type *IntPtrTy = TD->getIntPtrType(BB.getContext()); - Value* Offset = ConstantInt::get(IntPtrTy, - InstWriteOffset - DepWriteOffset); - // Offset the start of the memset with a GEP. As the memset type is - // i8* a GEP will do this without needing to use ptrtoint, etc. - Value *Dest = GetElementPtrInst::Create(DepIntrinsic->getRawDest(), - Offset, - "", - DepWrite); - DepIntrinsic->setDest(Dest); - MadeChange = true; - } } } diff --git a/test/Transforms/DeadStoreElimination/OverwriteStoreStart.ll b/test/Transforms/DeadStoreElimination/OverwriteStoreStart.ll deleted file mode 100644 index 56ba3f49270..00000000000 --- a/test/Transforms/DeadStoreElimination/OverwriteStoreStart.ll +++ /dev/null @@ -1,71 +0,0 @@ -; RUN: opt < %s -basicaa -dse -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-S128" - -%struct.vec2 = type { <4 x i32>, <4 x i32> } -%struct.vec2plusi = type { <4 x i32>, <4 x i32>, i32 } - -@glob1 = global %struct.vec2 zeroinitializer, align 16 -@glob2 = global %struct.vec2plusi zeroinitializer, align 16 - -define void @write4to8(i32* nocapture %p) nounwind uwtable ssp { -; CHECK: @write4to8 -entry: - %arrayidx0 = getelementptr inbounds i32* %p, i64 1 - %p3 = bitcast i32* %arrayidx0 to i8* -; CHECK: call void @llvm.memset.p0i8.i64(i8* %{{[0-9]+}}, i8 0, i64 24, i32 4, i1 false) - call void @llvm.memset.p0i8.i64(i8* %p3, i8 0, i64 28, i32 4, i1 false) - %arrayidx1 = getelementptr inbounds i32* %p, i64 1 - store i32 1, i32* %arrayidx1, align 4 - ret void -} - -define void @write4to12(i32* nocapture %p) nounwind uwtable ssp { -; CHECK: @write4to12 -entry: -%arrayidx0 = getelementptr inbounds i32* %p, i64 1 -%p3 = bitcast i32* %arrayidx0 to i8* -; CHECK: call void @llvm.memset.p0i8.i64(i8* %{{[0-9]+}}, i8 0, i64 20, i32 4, i1 false) -call void @llvm.memset.p0i8.i64(i8* %p3, i8 0, i64 28, i32 4, i1 false) -%arrayidx1 = bitcast i32* %arrayidx0 to i64* -store i64 1, i64* %arrayidx1, align 4 -ret void -} - -define void @write4to8_2(i32* nocapture %p) nounwind uwtable ssp { -; CHECK: @write4to8_2 -entry: -%arrayidx0 = getelementptr inbounds i32* %p, i64 1 -%p3 = bitcast i32* %arrayidx0 to i8* -; CHECK: call void @llvm.memset.p0i8.i64(i8* %{{[0-9]+}}, i8 0, i64 24, i32 4, i1 false) -call void @llvm.memset.p0i8.i64(i8* %p3, i8 0, i64 28, i32 4, i1 false) -%arrayidx1 = bitcast i32* %p to i64* -store i64 1, i64* %arrayidx1, align 4 -ret void -} - -define void @dontwrite4to6(i32* nocapture %p) nounwind uwtable ssp { -; CHECK: @dontwrite4to6 -entry: -%arrayidx0 = getelementptr inbounds i32* %p, i64 1 -%p3 = bitcast i32* %arrayidx0 to i8* -; CHECK: call void @llvm.memset.p0i8.i64(i8* %p3, i8 0, i64 28, i32 4, i1 false) -call void @llvm.memset.p0i8.i64(i8* %p3, i8 0, i64 28, i32 4, i1 false) -%arrayidx1 = bitcast i32* %arrayidx0 to i16* -store i16 1, i16* %arrayidx1, align 4 -ret void -} - -define void @write4to8_neg_gep(i32* nocapture %p) nounwind uwtable ssp { -; CHECK: @write4to8_neg_gep -entry: -%arrayidx0 = getelementptr inbounds i32* %p, i64 -1 -%p3 = bitcast i32* %arrayidx0 to i8* -; CHECK: call void @llvm.memset.p0i8.i64(i8* %{{[0-9]+}}, i8 0, i64 24, i32 4, i1 false) -call void @llvm.memset.p0i8.i64(i8* %p3, i8 0, i64 28, i32 4, i1 false) -%neg2 = getelementptr inbounds i32* %p, i64 -2 -%arrayidx1 = bitcast i32* %neg2 to i64* -store i64 1, i64* %arrayidx1, align 4 -ret void -} - -declare void @llvm.memset.p0i8.i64(i8* nocapture, i8, i64, i32, i1) nounwind