[llvm] r311429 - [X86] Prevent several calls to ISD::isConstantSplatVector from returning a narrower APInt than the original scalar type
Craig Topper via llvm-commits
llvm-commits at lists.llvm.org
Mon Aug 21 22:40:17 PDT 2017
Author: ctopper
Date: Mon Aug 21 22:40:17 2017
New Revision: 311429
URL: http://llvm.org/viewvc/llvm-project?rev=311429&view=rev
Log:
[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
Added:
llvm/trunk/test/CodeGen/X86/pr34271-1.ll
llvm/trunk/test/CodeGen/X86/pr34271.ll
Modified:
llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h
llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
Modified: llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h?rev=311429&r1=311428&r2=311429&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h (original)
+++ llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h Mon Aug 21 22:40:17 2017
@@ -85,7 +85,10 @@ namespace ISD {
/// If N is a BUILD_VECTOR node whose elements are all the same constant or
/// undefined, return true and return the constant value in \p SplatValue.
- bool isConstantSplatVector(const SDNode *N, APInt &SplatValue);
+ /// This sets \p SplatValue to the smallest possible splat unless AllowShrink
+ /// is set to false.
+ bool isConstantSplatVector(const SDNode *N, APInt &SplatValue,
+ bool AllowShrink = true);
/// Return true if the specified node is a BUILD_VECTOR where all of the
/// elements are ~0 or undef.
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp?rev=311429&r1=311428&r2=311429&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp Mon Aug 21 22:40:17 2017
@@ -116,7 +116,8 @@ bool ConstantFPSDNode::isValueValidForTy
// ISD Namespace
//===----------------------------------------------------------------------===//
-bool ISD::isConstantSplatVector(const SDNode *N, APInt &SplatVal) {
+bool ISD::isConstantSplatVector(const SDNode *N, APInt &SplatVal,
+ bool AllowShrink) {
auto *BV = dyn_cast<BuildVectorSDNode>(N);
if (!BV)
return false;
@@ -124,9 +125,11 @@ bool ISD::isConstantSplatVector(const SD
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
Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=311429&r1=311428&r2=311429&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Mon Aug 21 22:40:17 2017
@@ -29567,8 +29567,9 @@ static bool detectZextAbsDiff(const SDVa
// In SetLT case, The second operand of the comparison can be either 1 or 0.
APInt SplatVal;
if ((CC == ISD::SETLT) &&
- !((ISD::isConstantSplatVector(SetCC.getOperand(1).getNode(), SplatVal) &&
- SplatVal == 1) ||
+ !((ISD::isConstantSplatVector(SetCC.getOperand(1).getNode(), SplatVal,
+ /*AllowShrink*/false) &&
+ SplatVal.isOneValue()) ||
(ISD::isBuildVectorAllZeros(SetCC.getOperand(1).getNode()))))
return false;
@@ -32083,7 +32084,8 @@ static SDValue combineAndMaskToShift(SDN
return SDValue();
APInt SplatVal;
- if (!ISD::isConstantSplatVector(Op1.getNode(), SplatVal) ||
+ if (!ISD::isConstantSplatVector(Op1.getNode(), SplatVal,
+ /*AllowShrink*/false) ||
!SplatVal.isMask())
return SDValue();
@@ -32667,7 +32669,8 @@ static SDValue detectUSatPattern(SDValue
"Unexpected types for truncate operation");
APInt C;
- if (ISD::isConstantSplatVector(In.getOperand(1).getNode(), C)) {
+ if (ISD::isConstantSplatVector(In.getOperand(1).getNode(), C,
+ /*AllowShrink*/false)) {
// C should be equal to UINT32_MAX / UINT16_MAX / UINT8_MAX according
// the element size of the destination type.
return C.isMask(VT.getScalarSizeInBits()) ? In.getOperand(0) :
@@ -35374,7 +35377,8 @@ static SDValue combineIncDecVector(SDNod
SDNode *N1 = N->getOperand(1).getNode();
APInt SplatVal;
- if (!ISD::isConstantSplatVector(N1, SplatVal) || !SplatVal.isOneValue())
+ if (!ISD::isConstantSplatVector(N1, SplatVal, /*AllowShrink*/false) ||
+ !SplatVal.isOneValue())
return SDValue();
SDValue AllOnesVec = getOnesVector(VT, DAG, SDLoc(N));
Added: llvm/trunk/test/CodeGen/X86/pr34271-1.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/pr34271-1.ll?rev=311429&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/pr34271-1.ll (added)
+++ llvm/trunk/test/CodeGen/X86/pr34271-1.ll Mon Aug 21 22:40:17 2017
@@ -0,0 +1,14 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -mattr=avx512vl,avx512bw | FileCheck %s
+
+define <16 x i16> @foo(<16 x i32> %i) {
+; CHECK-LABEL: foo:
+; CHECK: # BB#0:
+; CHECK-NEXT: vpminud {{.*}}(%rip){1to16}, %zmm0, %zmm0
+; CHECK-NEXT: vpmovdw %zmm0, %ymm0
+; CHECK-NEXT: retq
+ %x3 = icmp ult <16 x i32> %i, <i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009>
+ %x5 = select <16 x i1> %x3, <16 x i32> %i, <16 x i32> <i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009, i32 16843009>
+ %x6 = trunc <16 x i32> %x5 to <16 x i16>
+ ret <16 x i16> %x6
+}
Added: llvm/trunk/test/CodeGen/X86/pr34271.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/pr34271.ll?rev=311429&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/pr34271.ll (added)
+++ llvm/trunk/test/CodeGen/X86/pr34271.ll Mon Aug 21 22:40:17 2017
@@ -0,0 +1,14 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu | FileCheck %s
+
+; CHECK: .LCPI0_0:
+; CHECK-NEXT: .zero 16,1
+
+define <4 x i32> @f(<4 x i32> %a) {
+; CHECK-LABEL: f:
+; CHECK: # BB#0:
+; CHECK-NEXT: paddd .LCPI0_0(%rip), %xmm0
+; CHECK-NEXT: retq
+ %v = add nuw nsw <4 x i32> %a, <i32 16843009, i32 16843009, i32 16843009, i32 16843009>
+ ret <4 x i32> %v
+}
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