From 4c81aa260209379a29ab4bce328160cb333daaf9 Mon Sep 17 00:00:00 2001 From: Pawel Bylica Date: Mon, 29 Jun 2015 20:28:47 +0000 Subject: [PATCH] [DAGCombiner] Fix & simplify constant folding of sext/zext. Summary: This patch fixes the cases of sext/zext constant folding in DAG combiner where constans do not fit 64 bits. The fix simply removes un$ Test Plan: New regression test included. Reviewers: RKSimon Reviewed By: RKSimon Subscribers: RKSimon, llvm-commits Differential Revision: http://reviews.llvm.org/D10607 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240991 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 24 +++--- test/CodeGen/X86/fold-vector-sext-crash2.ll | 92 +++++++++++++++++++++ 2 files changed, 103 insertions(+), 13 deletions(-) create mode 100644 test/CodeGen/X86/fold-vector-sext-crash2.ll diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 29f9df6425e..631f5852334 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -5579,12 +5579,12 @@ SDValue DAGCombiner::visitSETCC(SDNode *N) { SDLoc(N)); } -// tryToFoldExtendOfConstant - Try to fold a sext/zext/aext -// dag node into a ConstantSDNode or a build_vector of constants. -// This function is called by the DAGCombiner when visiting sext/zext/aext -// dag nodes (see for example method DAGCombiner::visitSIGN_EXTEND). -// Vector extends are not folded if operations are legal; this is to -// avoid introducing illegal build_vector dag nodes. +/// Try to fold a sext/zext/aext dag node into a ConstantSDNode or +/// a build_vector of constants. +/// This function is called by the DAGCombiner when visiting sext/zext/aext +/// dag nodes (see for example method DAGCombiner::visitSIGN_EXTEND). +/// Vector extends are not folded if operations are legal; this is to +/// avoid introducing illegal build_vector dag nodes. static SDNode *tryToFoldExtendOfConstant(SDNode *N, const TargetLowering &TLI, SelectionDAG &DAG, bool LegalTypes, bool LegalOperations) { @@ -5614,7 +5614,6 @@ static SDNode *tryToFoldExtendOfConstant(SDNode *N, const TargetLowering &TLI, // We can fold this node into a build_vector. unsigned VTBits = SVT.getSizeInBits(); unsigned EVTBits = N0->getValueType(0).getScalarType().getSizeInBits(); - unsigned ShAmt = VTBits - EVTBits; SmallVector Elts; unsigned NumElts = VT.getVectorNumElements(); SDLoc DL(N); @@ -5627,14 +5626,13 @@ static SDNode *tryToFoldExtendOfConstant(SDNode *N, const TargetLowering &TLI, } SDLoc DL(Op); - ConstantSDNode *CurrentND = cast(Op); - const APInt &C = APInt(VTBits, CurrentND->getAPIntValue().getZExtValue()); + // Get the constant value and if needed trunc it to the size of the type. + // Nodes like build_vector might have constants wider than the scalar type. + APInt C = cast(Op)->getAPIntValue().zextOrTrunc(EVTBits); if (Opcode == ISD::SIGN_EXTEND || Opcode == ISD::SIGN_EXTEND_VECTOR_INREG) - Elts.push_back(DAG.getConstant(C.shl(ShAmt).ashr(ShAmt).getZExtValue(), - DL, SVT)); + Elts.push_back(DAG.getConstant(C.sext(VTBits), DL, SVT)); else - Elts.push_back(DAG.getConstant(C.shl(ShAmt).lshr(ShAmt).getZExtValue(), - DL, SVT)); + Elts.push_back(DAG.getConstant(C.zext(VTBits), DL, SVT)); } return DAG.getNode(ISD::BUILD_VECTOR, DL, VT, Elts).getNode(); diff --git a/test/CodeGen/X86/fold-vector-sext-crash2.ll b/test/CodeGen/X86/fold-vector-sext-crash2.ll new file mode 100644 index 00000000000..44c836195ab --- /dev/null +++ b/test/CodeGen/X86/fold-vector-sext-crash2.ll @@ -0,0 +1,92 @@ +; RUN: llc < %s -march=x86 | FileCheck %s -check-prefix=X32 +; RUN: llc < %s -march=x86-64 | FileCheck %s -check-prefix=X64 + +; DAGCombiner crashes during sext folding + +define <2 x i256> @test_sext1() { + %Se = sext <2 x i8> to <2 x i256> + %Shuff = shufflevector <2 x i256> zeroinitializer, <2 x i256> %Se, <2 x i32> + ret <2 x i256> %Shuff + + ; X64-LABEL: test_sext1 + ; X64: movq $-1 + ; X64-NEXT: movq $-1 + ; X64-NEXT: movq $-1 + ; X64-NEXT: movq $-99 + + ; X32-LABEL: test_sext1 + ; X32: movl $-1 + ; X32-NEXT: movl $-1 + ; X32-NEXT: movl $-1 + ; X32-NEXT: movl $-1 + ; X32-NEXT: movl $-1 + ; X32-NEXT: movl $-1 + ; X32-NEXT: movl $-1 + ; X32-NEXT: movl $-99 +} + +define <2 x i256> @test_sext2() { + %Se = sext <2 x i128> to <2 x i256> + %Shuff = shufflevector <2 x i256> zeroinitializer, <2 x i256> %Se, <2 x i32> + ret <2 x i256> %Shuff + + ; X64-LABEL: test_sext2 + ; X64: movq $-1 + ; X64-NEXT: movq $-1 + ; X64-NEXT: movq $-1 + ; X64-NEXT: movq $-1999 + + ; X32-LABEL: test_sext2 + ; X32: movl $-1 + ; X32-NEXT: movl $-1 + ; X32-NEXT: movl $-1 + ; X32-NEXT: movl $-1 + ; X32-NEXT: movl $-1 + ; X32-NEXT: movl $-1 + ; X32-NEXT: movl $-1 + ; X32-NEXT: movl $-1999 +} + +define <2 x i256> @test_zext1() { + %Se = zext <2 x i8> to <2 x i256> + %Shuff = shufflevector <2 x i256> zeroinitializer, <2 x i256> %Se, <2 x i32> + ret <2 x i256> %Shuff + + ; X64-LABEL: test_zext1 + ; X64: movq $0 + ; X64-NEXT: movq $0 + ; X64-NEXT: movq $0 + ; X64-NEXT: movq $254 + + ; X32-LABEL: test_zext1 + ; X32: movl $0 + ; X32-NEXT: movl $0 + ; X32-NEXT: movl $0 + ; X32-NEXT: movl $0 + ; X32-NEXT: movl $0 + ; X32-NEXT: movl $0 + ; X32-NEXT: movl $0 + ; X32-NEXT: movl $254 +} + +define <2 x i256> @test_zext2() { + %Se = zext <2 x i128> to <2 x i256> + %Shuff = shufflevector <2 x i256> zeroinitializer, <2 x i256> %Se, <2 x i32> + ret <2 x i256> %Shuff + + ; X64-LABEL: test_zext2 + ; X64: movq $0 + ; X64-NEXT: movq $0 + ; X64-NEXT: movq $-1 + ; X64-NEXT: movq $-2 + + ; X32-LABEL: test_zext2 + ; X32: movl $0 + ; X32-NEXT: movl $0 + ; X32-NEXT: movl $0 + ; X32-NEXT: movl $0 + ; X32-NEXT: movl $-1 + ; X32-NEXT: movl $-1 + ; X32-NEXT: movl $-1 + ; X32-NEXT: movl $-2 +} -- 2.34.1