From a0b2af46a54dc5a3fd8f27deed78828d1833e97a Mon Sep 17 00:00:00 2001 From: David Majnemer Date: Mon, 1 Sep 2014 21:10:02 +0000 Subject: [PATCH] Revert "Revert two GEP-related InstCombine commits" This reverts commit r216698 which reverted r216523 and r216598. We would attempt to perform the transformation even if the match() failed because, as a side effect, it would set V. This would trick us into believing that we correctly found a place to correctly apply the transform. An additional test case was added to getelementptr.ll so that we might not regress in the future. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216890 91177308-0d34-0410-b5e6-96231b3b80d8 --- .../InstCombine/InstructionCombining.cpp | 53 +++++++++++--- test/Transforms/InstCombine/getelementptr.ll | 73 +++++++++++++++++++ 2 files changed, 115 insertions(+), 11 deletions(-) diff --git a/lib/Transforms/InstCombine/InstructionCombining.cpp b/lib/Transforms/InstCombine/InstructionCombining.cpp index f01dca7fab8..a95f5784fa5 100644 --- a/lib/Transforms/InstCombine/InstructionCombining.cpp +++ b/lib/Transforms/InstCombine/InstructionCombining.cpp @@ -1508,19 +1508,50 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) { GetElementPtrInst::Create(Src->getOperand(0), Indices, GEP.getName()); } - // Canonicalize (gep i8* X, -(ptrtoint Y)) to (sub (ptrtoint X), (ptrtoint Y)) - // The GEP pattern is emitted by the SCEV expander for certain kinds of - // pointer arithmetic. - if (DL && GEP.getNumIndices() == 1 && - match(GEP.getOperand(1), m_Neg(m_PtrToInt(m_Value())))) { + if (DL && GEP.getNumIndices() == 1) { unsigned AS = GEP.getPointerAddressSpace(); - if (GEP.getType() == Builder->getInt8PtrTy(AS) && - GEP.getOperand(1)->getType()->getScalarSizeInBits() == + if (GEP.getOperand(1)->getType()->getScalarSizeInBits() == DL->getPointerSizeInBits(AS)) { - Operator *Index = cast(GEP.getOperand(1)); - Value *PtrToInt = Builder->CreatePtrToInt(PtrOp, Index->getType()); - Value *NewSub = Builder->CreateSub(PtrToInt, Index->getOperand(1)); - return CastInst::Create(Instruction::IntToPtr, NewSub, GEP.getType()); + Type *PtrTy = GEP.getPointerOperandType(); + Type *Ty = PtrTy->getPointerElementType(); + uint64_t TyAllocSize = DL->getTypeAllocSize(Ty); + + bool Matched = false; + uint64_t C; + Value *V = nullptr; + if (TyAllocSize == 1) { + V = GEP.getOperand(1); + Matched = true; + } else if (match(GEP.getOperand(1), + m_AShr(m_Value(V), m_ConstantInt(C)))) { + if (TyAllocSize == 1ULL << C) + Matched = true; + } else if (match(GEP.getOperand(1), + m_SDiv(m_Value(V), m_ConstantInt(C)))) { + if (TyAllocSize == C) + Matched = true; + } + + if (Matched) { + // Canonicalize (gep i8* X, -(ptrtoint Y)) + // to (inttoptr (sub (ptrtoint X), (ptrtoint Y))) + // The GEP pattern is emitted by the SCEV expander for certain kinds of + // pointer arithmetic. + if (match(V, m_Neg(m_PtrToInt(m_Value())))) { + Operator *Index = cast(V); + Value *PtrToInt = Builder->CreatePtrToInt(PtrOp, Index->getType()); + Value *NewSub = Builder->CreateSub(PtrToInt, Index->getOperand(1)); + return CastInst::Create(Instruction::IntToPtr, NewSub, GEP.getType()); + } + // Canonicalize (gep i8* X, (ptrtoint Y)-(ptrtoint X)) + // to (bitcast Y) + Value *Y; + if (match(V, m_Sub(m_PtrToInt(m_Value(Y)), + m_PtrToInt(m_Specific(GEP.getOperand(0)))))) { + return CastInst::CreatePointerBitCastOrAddrSpaceCast(Y, + GEP.getType()); + } + } } } diff --git a/test/Transforms/InstCombine/getelementptr.ll b/test/Transforms/InstCombine/getelementptr.ll index da91ada0805..b7daccc71af 100644 --- a/test/Transforms/InstCombine/getelementptr.ll +++ b/test/Transforms/InstCombine/getelementptr.ll @@ -6,6 +6,7 @@ target datalayout = "e-p:64:64-p1:16:16-p2:32:32:32-p3:64:64:64" %pair = type { i32, i32 } %struct.B = type { double } %struct.A = type { %struct.B, i32, i32 } +%struct.C = type { [7 x i8] } @Global = constant [10 x i8] c"helloworld" @@ -813,6 +814,78 @@ define i16 @test41([3 x i32] addrspace(1)* %array) { ; CHECK-NEXT: ret i16 8 } +define i8* @test42(i8* %c1, i8* %c2) { + %ptrtoint = ptrtoint i8* %c1 to i64 + %sub = sub i64 0, %ptrtoint + %gep = getelementptr inbounds i8* %c2, i64 %sub + ret i8* %gep + +; CHECK-LABEL: @test42( +; CHECK-NEXT: [[PTRTOINT1:%.*]] = ptrtoint i8* %c1 to i64 +; CHECK-NEXT: [[PTRTOINT2:%.*]] = ptrtoint i8* %c2 to i64 +; CHECK-NEXT: [[SUB:%.*]] = sub i64 [[PTRTOINT2]], [[PTRTOINT1]] +; CHECK-NEXT: [[INTTOPTR:%.*]] = inttoptr i64 [[SUB]] to i8* +; CHECK-NEXT: ret i8* [[INTTOPTR]] +} + +define i16* @test43(i16* %c1, i16* %c2) { + %ptrtoint = ptrtoint i16* %c1 to i64 + %sub = sub i64 0, %ptrtoint + %shr = ashr i64 %sub, 1 + %gep = getelementptr inbounds i16* %c2, i64 %shr + ret i16* %gep + +; CHECK-LABEL: @test43( +; CHECK-NEXT: [[PTRTOINT1:%.*]] = ptrtoint i16* %c1 to i64 +; CHECK-NEXT: [[PTRTOINT2:%.*]] = ptrtoint i16* %c2 to i64 +; CHECK-NEXT: [[SUB:%.*]] = sub i64 [[PTRTOINT2]], [[PTRTOINT1]] +; CHECK-NEXT: [[INTTOPTR:%.*]] = inttoptr i64 [[SUB]] to i16* +; CHECK-NEXT: ret i16* [[INTTOPTR]] +} + +define %struct.C* @test44(%struct.C* %c1, %struct.C* %c2) { + %ptrtoint = ptrtoint %struct.C* %c1 to i64 + %sub = sub i64 0, %ptrtoint + %shr = sdiv i64 %sub, 7 + %gep = getelementptr inbounds %struct.C* %c2, i64 %shr + ret %struct.C* %gep + +; CHECK-LABEL: @test44( +; CHECK-NEXT: [[PTRTOINT1:%.*]] = ptrtoint %struct.C* %c1 to i64 +; CHECK-NEXT: [[PTRTOINT2:%.*]] = ptrtoint %struct.C* %c2 to i64 +; CHECK-NEXT: [[SUB:%.*]] = sub i64 [[PTRTOINT2]], [[PTRTOINT1]] +; CHECK-NEXT: [[INTTOPTR:%.*]] = inttoptr i64 [[SUB]] to %struct.C* +; CHECK-NEXT: ret %struct.C* [[INTTOPTR]] +} + +define %struct.C* @test45(%struct.C* %c1, %struct.C** %c2) { + %ptrtoint1 = ptrtoint %struct.C* %c1 to i64 + %ptrtoint2 = ptrtoint %struct.C** %c2 to i64 + %sub = sub i64 %ptrtoint2, %ptrtoint1 ; C2 - C1 + %shr = sdiv i64 %sub, 7 + %gep = getelementptr inbounds %struct.C* %c1, i64 %shr ; C1 + (C2 - C1) + ret %struct.C* %gep + +; CHECK-LABEL: @test45( +; CHECK-NEXT: [[BITCAST:%.*]] = bitcast %struct.C** %c2 to %struct.C* +; CHECK-NEXT: ret %struct.C* [[BITCAST]] +} + +define %struct.C* @test46(%struct.C* %c1, %struct.C* %c2, i64 %N) { + %ptrtoint = ptrtoint %struct.C* %c1 to i64 + %sub = sub i64 0, %ptrtoint + %sdiv = sdiv i64 %sub, %N + %gep = getelementptr inbounds %struct.C* %c2, i64 %sdiv + ret %struct.C* %gep + +; CHECK-LABEL: @test46( +; CHECK-NEXT: [[PTRTOINT:%.*]] = ptrtoint %struct.C* %c1 to i64 +; CHECK-NEXT: [[SUB:%.*]] = sub i64 0, [[PTRTOINT]] +; CHECK-NEXT: [[SDIV:%.*]] = sdiv i64 [[SUB]], %N +; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds %struct.C* %c2, i64 %sdiv +; CHECK-NEXT: ret %struct.C* [[GEP]] +} + define i32 addrspace(1)* @ascast_0_gep(i32* %p) nounwind { ; CHECK-LABEL: @ascast_0_gep( ; CHECK-NOT: getelementptr