spatel updated this revision to Diff 41699. spatel added a comment. Patch updated with suggestions from http://reviews.llvm.org/D14891:
1. Changed 'else if' to plain 'if' for RHS check. 2. Used 'auto*' for dyn_casted vars. 3. Replaced 'getNUses() == 0' with 'use_empty()'. http://reviews.llvm.org/D15165 Files: lib/CodeGen/CGExprScalar.cpp test/CodeGen/fp-contract-pragma.cpp Index: test/CodeGen/fp-contract-pragma.cpp =================================================================== --- test/CodeGen/fp-contract-pragma.cpp +++ 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: lib/CodeGen/CGExprScalar.cpp =================================================================== --- lib/CodeGen/CGExprScalar.cpp +++ 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;
Index: test/CodeGen/fp-contract-pragma.cpp =================================================================== --- test/CodeGen/fp-contract-pragma.cpp +++ 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: lib/CodeGen/CGExprScalar.cpp =================================================================== --- lib/CodeGen/CGExprScalar.cpp +++ 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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