From b49f0893b24dae441f8ff309c782705e5e066bd1 Mon Sep 17 00:00:00 2001 From: Craig Topper Date: Tue, 22 Aug 2017 05:40:17 +0000 Subject: [X86] Prevent several calls to ISD::isConstantSplatVector from returning a narrower APInt than the original scalar type ISD::isConstantSplatVector can shrink to the smallest splat width. But we don't check the size of the resulting APInt at all. This can cause us to misinterpret the results. This patch just adds a flag to prevent the APInt from changing width. Fixes PR34271. Differential Revision: https://reviews.llvm.org/D36996 llvm-svn: 311429 --- llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) (limited to 'llvm/lib/CodeGen/SelectionDAG') diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index 508316a1fad..6489ca57b33 100644 --- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -116,7 +116,8 @@ bool ConstantFPSDNode::isValueValidForType(EVT VT, // ISD Namespace //===----------------------------------------------------------------------===// -bool ISD::isConstantSplatVector(const SDNode *N, APInt &SplatVal) { +bool ISD::isConstantSplatVector(const SDNode *N, APInt &SplatVal, + bool AllowShrink) { auto *BV = dyn_cast(N); if (!BV) return false; @@ -124,9 +125,11 @@ bool ISD::isConstantSplatVector(const SDNode *N, APInt &SplatVal) { APInt SplatUndef; unsigned SplatBitSize; bool HasUndefs; - EVT EltVT = N->getValueType(0).getVectorElementType(); - return BV->isConstantSplat(SplatVal, SplatUndef, SplatBitSize, HasUndefs) && - EltVT.getSizeInBits() >= SplatBitSize; + unsigned EltSize = N->getValueType(0).getVectorElementType().getSizeInBits(); + unsigned MinSplatBits = AllowShrink ? 0 : EltSize; + return BV->isConstantSplat(SplatVal, SplatUndef, SplatBitSize, HasUndefs, + MinSplatBits) && + EltSize >= SplatBitSize; } // FIXME: AllOnes and AllZeros duplicate a lot of code. Could these be -- cgit v1.2.3