[llvm] r326237 - [ValueTracking] Teach cannotBeOrderedLessThanZeroImpl to look through ExtractElement.
Craig Topper via llvm-commits
llvm-commits at lists.llvm.org
Tue Feb 27 11:53:45 PST 2018
Author: ctopper
Date: Tue Feb 27 11:53:45 2018
New Revision: 326237
URL: http://llvm.org/viewvc/llvm-project?rev=326237&view=rev
Log:
[ValueTracking] Teach cannotBeOrderedLessThanZeroImpl to look through ExtractElement.
This is similar to what's done in computeKnownBits and computeSignBits. Don't do anything fancy just collect information valid for any element.
Differential Revision: https://reviews.llvm.org/D43789
Modified:
llvm/trunk/lib/Analysis/ValueTracking.cpp
llvm/trunk/test/Transforms/InstSimplify/floating-point-arithmetic.ll
Modified: llvm/trunk/lib/Analysis/ValueTracking.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ValueTracking.cpp?rev=326237&r1=326236&r2=326237&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ValueTracking.cpp (original)
+++ llvm/trunk/lib/Analysis/ValueTracking.cpp Tue Feb 27 11:53:45 2018
@@ -2783,6 +2783,12 @@ static bool cannotBeOrderedLessThanZeroI
// Widening/narrowing never change sign.
return cannotBeOrderedLessThanZeroImpl(I->getOperand(0), TLI, SignBitOnly,
Depth + 1);
+ case Instruction::ExtractElement:
+ // Look through extract element. At the moment we keep this simple and skip
+ // tracking the specific element. But at least we might find information
+ // valid for all elements of the vector.
+ return cannotBeOrderedLessThanZeroImpl(I->getOperand(0), TLI, SignBitOnly,
+ Depth + 1);
case Instruction::Call:
const auto *CI = cast<CallInst>(I);
Intrinsic::ID IID = getIntrinsicForCallSite(CI, TLI);
Modified: llvm/trunk/test/Transforms/InstSimplify/floating-point-arithmetic.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstSimplify/floating-point-arithmetic.ll?rev=326237&r1=326236&r2=326237&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstSimplify/floating-point-arithmetic.ll (original)
+++ llvm/trunk/test/Transforms/InstSimplify/floating-point-arithmetic.ll Tue Feb 27 11:53:45 2018
@@ -435,3 +435,17 @@ define float @fabs_sqrt_nnan_fabs(float
%fabs = call float @llvm.fabs.f32(float %sqrt)
ret float %fabs
}
+
+define float @fabs_select_positive_constants_vector_extract(i32 %c) {
+; CHECK-LABEL: @fabs_select_positive_constants_vector_extract(
+; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[C:%.*]], 0
+; CHECK-NEXT: [[SELECT:%.*]] = select i1 [[CMP]], <2 x float> <float 1.000000e+00, float 1.000000e+00>, <2 x float> <float 2.000000e+00, float 2.000000e+00>
+; CHECK-NEXT: [[EXTRACT:%.*]] = extractelement <2 x float> [[SELECT]], i32 0
+; CHECK-NEXT: ret float [[EXTRACT]]
+;
+ %cmp = icmp eq i32 %c, 0
+ %select = select i1 %cmp, <2 x float> <float 1.0, float 1.0>, <2 x float> <float 2.0, float 2.0>
+ %extract = extractelement <2 x float> %select, i32 0
+ %fabs = call float @llvm.fabs.f32(float %extract)
+ ret float %fabs
+}
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