[llvm] r330126 - [InstCombine] simplify fneg+fadd folds; NFC
Sanjay Patel via llvm-commits
llvm-commits at lists.llvm.org
Mon Apr 16 07:13:57 PDT 2018
Author: spatel
Date: Mon Apr 16 07:13:57 2018
New Revision: 330126
URL: http://llvm.org/viewvc/llvm-project?rev=330126&view=rev
Log:
[InstCombine] simplify fneg+fadd folds; NFC
Two cleanups:
1. As noted in D45453, we had tests that don't need FMF that were misplaced in the 'fast-math.ll' test file.
2. This removes the final uses of dyn_castFNegVal, so that can be deleted. We use 'match' now.
Added:
llvm/trunk/test/Transforms/InstCombine/fadd.ll
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp
llvm/trunk/lib/Transforms/InstCombine/InstCombineInternal.h
llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
llvm/trunk/test/Transforms/InstCombine/fast-math.ll
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp?rev=330126&r1=330125&r2=330126&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp Mon Apr 16 07:13:57 2018
@@ -1308,14 +1308,13 @@ Instruction *InstCombiner::visitFAdd(Bin
if (Instruction *FoldedFAdd = foldBinOpIntoSelectOrPhi(I))
return FoldedFAdd;
- // -A + B --> B - A
- if (Value *LHSV = dyn_castFNegVal(LHS))
- return BinaryOperator::CreateFSubFMF(RHS, LHSV, &I);
-
- // A + -B --> A - B
- if (!isa<Constant>(RHS))
- if (Value *V = dyn_castFNegVal(RHS))
- return BinaryOperator::CreateFSubFMF(LHS, V, &I);
+ Value *X;
+ // (-X) + Y --> Y - X
+ if (match(LHS, m_FNeg(m_Value(X))))
+ return BinaryOperator::CreateFSubFMF(RHS, X, &I);
+ // Y + (-X) --> Y - X
+ if (match(RHS, m_FNeg(m_Value(X))))
+ return BinaryOperator::CreateFSubFMF(LHS, X, &I);
// Check for (fadd double (sitofp x), y), see if we can merge this into an
// integer add followed by a promotion.
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineInternal.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineInternal.h?rev=330126&r1=330125&r2=330126&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineInternal.h (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineInternal.h Mon Apr 16 07:13:57 2018
@@ -376,7 +376,6 @@ private:
bool shouldChangeType(unsigned FromBitWidth, unsigned ToBitWidth) const;
bool shouldChangeType(Type *From, Type *To) const;
Value *dyn_castNegVal(Value *V) const;
- Value *dyn_castFNegVal(Value *V, bool NoSignedZero = false) const;
Type *FindElementAtOffset(PointerType *PtrTy, int64_t Offset,
SmallVectorImpl<Value *> &NewIndices);
Modified: llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp?rev=330126&r1=330125&r2=330126&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp Mon Apr 16 07:13:57 2018
@@ -790,23 +790,6 @@ Value *InstCombiner::dyn_castNegVal(Valu
return nullptr;
}
-/// Given a 'fsub' instruction, return the RHS of the instruction if the LHS is
-/// a constant negative zero (which is the 'negate' form).
-Value *InstCombiner::dyn_castFNegVal(Value *V, bool IgnoreZeroSign) const {
- if (BinaryOperator::isFNeg(V, IgnoreZeroSign))
- return BinaryOperator::getFNegArgument(V);
-
- // Constants can be considered to be negated values if they can be folded.
- if (ConstantFP *C = dyn_cast<ConstantFP>(V))
- return ConstantExpr::getFNeg(C);
-
- if (ConstantDataVector *C = dyn_cast<ConstantDataVector>(V))
- if (C->getType()->getElementType()->isFloatingPointTy())
- return ConstantExpr::getFNeg(C);
-
- return nullptr;
-}
-
static Value *foldOperationIntoSelectOperand(Instruction &I, Value *SO,
InstCombiner::BuilderTy &Builder) {
if (auto *Cast = dyn_cast<CastInst>(&I))
Added: llvm/trunk/test/Transforms/InstCombine/fadd.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/fadd.ll?rev=330126&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/fadd.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/fadd.ll Mon Apr 16 07:13:57 2018
@@ -0,0 +1,27 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+; -x + y => y - x
+
+define float @fneg_op0(float %x, float %y) {
+; CHECK-LABEL: @fneg_op0(
+; CHECK-NEXT: [[ADD:%.*]] = fsub float [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT: ret float [[ADD]]
+;
+ %neg = fsub float -0.0, %x
+ %add = fadd float %neg, %y
+ ret float %add
+}
+
+; x + -y => x - y
+
+define float @fneg_op1(float %x, float %y) {
+; CHECK-LABEL: @fneg_op1(
+; CHECK-NEXT: [[ADD:%.*]] = fsub float [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT: ret float [[ADD]]
+;
+ %neg = fsub float -0.0, %y
+ %add = fadd float %x, %neg
+ ret float %add
+}
+
Modified: llvm/trunk/test/Transforms/InstCombine/fast-math.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/fast-math.ll?rev=330126&r1=330125&r2=330126&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/fast-math.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/fast-math.ll Mon Apr 16 07:13:57 2018
@@ -406,30 +406,6 @@ define float @fold13_reassoc(float %x) {
ret float %sub
}
-; -x + y => y - x
-; This is always safe. No FMF required.
-define float @fold14(float %x, float %y) {
-; CHECK-LABEL: @fold14(
-; CHECK-NEXT: [[ADD:%.*]] = fsub float [[Y:%.*]], [[X:%.*]]
-; CHECK-NEXT: ret float [[ADD]]
-;
- %neg = fsub float -0.0, %x
- %add = fadd float %neg, %y
- ret float %add
-}
-
-; x + -y => x - y
-; This is always safe. No FMF required.
-define float @fold15(float %x, float %y) {
-; CHECK-LABEL: @fold15(
-; CHECK-NEXT: [[ADD:%.*]] = fsub float [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT: ret float [[ADD]]
-;
- %neg = fsub float -0.0, %y
- %add = fadd float %x, %neg
- ret float %add
-}
-
; (select X+Y, X-Y) => X + (select Y, -Y)
; This is always safe. No FMF required.
define float @fold16(float %x, float %y) {
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