craig.topper created this revision.
craig.topper added reviewers: cameron.mcinally, rjmccall, efriedma, rsmith.
We have an fneg instruction now and should use it instead of the fsub -0.0
idiom. Looks like we had no test that showed that we handled the negation cases
here so I've added new tests.
https://reviews.llvm.org/D72010
Files:
clang/lib/CodeGen/CGExprScalar.cpp
clang/test/CodeGen/fp-contract-pragma.cpp
Index: clang/test/CodeGen/fp-contract-pragma.cpp
===================================================================
--- clang/test/CodeGen/fp-contract-pragma.cpp
+++ clang/test/CodeGen/fp-contract-pragma.cpp
@@ -74,3 +74,18 @@
return (a = 2 * b) - c;
}
+float fp_contract_8(float a, float b, float c) {
+// CHECK: _Z13fp_contract_8fff
+// CHECK: fneg float %c
+// CHECK: tail call float @llvm.fmuladd
+ #pragma STDC FP_CONTRACT ON
+ return a * b - c;
+}
+
+float fp_contract_9(float a, float b, float c) {
+// CHECK: _Z13fp_contract_9fff
+// CHECK: fneg float %a
+// CHECK: tail call float @llvm.fmuladd
+ #pragma STDC FP_CONTRACT ON
+ return c - a * b;
+}
Index: clang/lib/CodeGen/CGExprScalar.cpp
===================================================================
--- clang/lib/CodeGen/CGExprScalar.cpp
+++ clang/lib/CodeGen/CGExprScalar.cpp
@@ -3345,17 +3345,10 @@
Value *MulOp0 = MulOp->getOperand(0);
Value *MulOp1 = MulOp->getOperand(1);
- if (negMul) {
- MulOp0 =
- Builder.CreateFSub(
- llvm::ConstantFP::getZeroValueForNegation(MulOp0->getType()), MulOp0,
- "neg");
- } else if (negAdd) {
- Addend =
- Builder.CreateFSub(
- llvm::ConstantFP::getZeroValueForNegation(Addend->getType()), Addend,
- "neg");
- }
+ if (negMul)
+ MulOp0 = Builder.CreateFNeg(MulOp0, "neg");
+ if (negAdd)
+ Addend = Builder.CreateFNeg(Addend, "neg");
Value *FMulAdd = Builder.CreateCall(
CGF.CGM.getIntrinsic(llvm::Intrinsic::fmuladd, Addend->getType()),
Index: clang/test/CodeGen/fp-contract-pragma.cpp
===================================================================
--- clang/test/CodeGen/fp-contract-pragma.cpp
+++ clang/test/CodeGen/fp-contract-pragma.cpp
@@ -74,3 +74,18 @@
return (a = 2 * b) - c;
}
+float fp_contract_8(float a, float b, float c) {
+// CHECK: _Z13fp_contract_8fff
+// CHECK: fneg float %c
+// CHECK: tail call float @llvm.fmuladd
+ #pragma STDC FP_CONTRACT ON
+ return a * b - c;
+}
+
+float fp_contract_9(float a, float b, float c) {
+// CHECK: _Z13fp_contract_9fff
+// CHECK: fneg float %a
+// CHECK: tail call float @llvm.fmuladd
+ #pragma STDC FP_CONTRACT ON
+ return c - a * b;
+}
Index: clang/lib/CodeGen/CGExprScalar.cpp
===================================================================
--- clang/lib/CodeGen/CGExprScalar.cpp
+++ clang/lib/CodeGen/CGExprScalar.cpp
@@ -3345,17 +3345,10 @@
Value *MulOp0 = MulOp->getOperand(0);
Value *MulOp1 = MulOp->getOperand(1);
- if (negMul) {
- MulOp0 =
- Builder.CreateFSub(
- llvm::ConstantFP::getZeroValueForNegation(MulOp0->getType()), MulOp0,
- "neg");
- } else if (negAdd) {
- Addend =
- Builder.CreateFSub(
- llvm::ConstantFP::getZeroValueForNegation(Addend->getType()), Addend,
- "neg");
- }
+ if (negMul)
+ MulOp0 = Builder.CreateFNeg(MulOp0, "neg");
+ if (negAdd)
+ Addend = Builder.CreateFNeg(Addend, "neg");
Value *FMulAdd = Builder.CreateCall(
CGF.CGM.getIntrinsic(llvm::Intrinsic::fmuladd, Addend->getType()),
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