[PATCH] D15165: change an assert when generating fmuladd to an ordinary 'if' check (PR25719)
Sanjay Patel via cfe-commits
cfe-commits at lists.llvm.org
Wed Dec 2 17:28:07 PST 2015
This revision was automatically updated to reflect the committed changes.
Closed by commit rL254573: change an assert when generating fmuladd to an ordinary 'if' check (PR25719) (authored by spatel).
Changed prior to commit:
http://reviews.llvm.org/D15165?vs=41699&id=41702#toc
Repository:
rL LLVM
http://reviews.llvm.org/D15165
Files:
cfe/trunk/lib/CodeGen/CGExprScalar.cpp
cfe/trunk/test/CodeGen/fp-contract-pragma.cpp
Index: cfe/trunk/test/CodeGen/fp-contract-pragma.cpp
===================================================================
--- cfe/trunk/test/CodeGen/fp-contract-pragma.cpp
+++ cfe/trunk/test/CodeGen/fp-contract-pragma.cpp
@@ -62,3 +62,15 @@
return a * b + c;
}
+// If the multiply has multiple uses, don't produce fmuladd.
+// This used to assert (PR25719):
+// https://llvm.org/bugs/show_bug.cgi?id=25719
+
+float fp_contract_7(float a, float b, float c) {
+// CHECK: _Z13fp_contract_7fff
+// CHECK: %mul = fmul float %b, 2.000000e+00
+// CHECK-NEXT: fsub float %mul, %c
+ #pragma STDC FP_CONTRACT ON
+ return (a = 2 * b) - c;
+}
+
Index: cfe/trunk/lib/CodeGen/CGExprScalar.cpp
===================================================================
--- cfe/trunk/lib/CodeGen/CGExprScalar.cpp
+++ cfe/trunk/lib/CodeGen/CGExprScalar.cpp
@@ -2564,19 +2564,17 @@
return nullptr;
// We have a potentially fusable op. Look for a mul on one of the operands.
- if (llvm::BinaryOperator* LHSBinOp = dyn_cast<llvm::BinaryOperator>(op.LHS)) {
- if (LHSBinOp->getOpcode() == llvm::Instruction::FMul) {
- assert(LHSBinOp->getNumUses() == 0 &&
- "Operations with multiple uses shouldn't be contracted.");
+ // Also, make sure that the mul result isn't used directly. In that case,
+ // there's no point creating a muladd operation.
+ if (auto *LHSBinOp = dyn_cast<llvm::BinaryOperator>(op.LHS)) {
+ if (LHSBinOp->getOpcode() == llvm::Instruction::FMul &&
+ LHSBinOp->use_empty())
return buildFMulAdd(LHSBinOp, op.RHS, CGF, Builder, false, isSub);
- }
- } else if (llvm::BinaryOperator* RHSBinOp =
- dyn_cast<llvm::BinaryOperator>(op.RHS)) {
- if (RHSBinOp->getOpcode() == llvm::Instruction::FMul) {
- assert(RHSBinOp->getNumUses() == 0 &&
- "Operations with multiple uses shouldn't be contracted.");
+ }
+ if (auto *RHSBinOp = dyn_cast<llvm::BinaryOperator>(op.RHS)) {
+ if (RHSBinOp->getOpcode() == llvm::Instruction::FMul &&
+ RHSBinOp->use_empty())
return buildFMulAdd(RHSBinOp, op.LHS, CGF, Builder, isSub, false);
- }
}
return nullptr;
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