Author: anemet Date: Tue Apr 4 16:18:30 2017 New Revision: 299469 URL: http://llvm.org/viewvc/llvm-project?rev=299469&view=rev Log: Set FMF for -ffp-contract=fast
With this, FMF(contract) becomes an alternative way to express the request to contract. These are currently only propagated for FMul, FAdd and FSub. The rest will be added as more FMFs are hooked up for this. This is toward fixing PR25721. Differential Revision: https://reviews.llvm.org/D31168 Added: cfe/trunk/test/CodeGen/ffp-contract-fast-option.cpp Modified: cfe/trunk/lib/CodeGen/CGExprScalar.cpp Modified: cfe/trunk/lib/CodeGen/CGExprScalar.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprScalar.cpp?rev=299469&r1=299468&r2=299469&view=diff ============================================================================== --- cfe/trunk/lib/CodeGen/CGExprScalar.cpp (original) +++ cfe/trunk/lib/CodeGen/CGExprScalar.cpp Tue Apr 4 16:18:30 2017 @@ -113,6 +113,22 @@ static bool CanElideOverflowCheck(const (2 * Ctx.getTypeSize(RHSTy)) < PromotedSize; } +/// Update the FastMathFlags of LLVM IR from the FPOptions in LangOptions. +static void updateFastMathFlags(llvm::FastMathFlags &FMF, + FPOptions FPFeatures) { + FMF.setAllowContract(FPFeatures.allowFPContractAcrossStatement()); +} + +/// Propagate fast-math flags from \p Op to the instruction in \p V. +static Value *propagateFMFlags(Value *V, const BinOpInfo &Op) { + if (auto *I = dyn_cast<llvm::Instruction>(V)) { + llvm::FastMathFlags FMF = I->getFastMathFlags(); + updateFastMathFlags(FMF, Op.FPFeatures); + I->setFastMathFlags(FMF); + } + return V; +} + class ScalarExprEmitter : public StmtVisitor<ScalarExprEmitter, Value*> { CodeGenFunction &CGF; @@ -553,8 +569,10 @@ public: !CanElideOverflowCheck(CGF.getContext(), Ops)) return EmitOverflowCheckedBinOp(Ops); - if (Ops.LHS->getType()->isFPOrFPVectorTy()) - return Builder.CreateFMul(Ops.LHS, Ops.RHS, "mul"); + if (Ops.LHS->getType()->isFPOrFPVectorTy()) { + Value *V = Builder.CreateFMul(Ops.LHS, Ops.RHS, "mul"); + return propagateFMFlags(V, Ops); + } return Builder.CreateMul(Ops.LHS, Ops.RHS, "mul"); } /// Create a binary op that checks for overflow. @@ -2722,7 +2740,8 @@ Value *ScalarExprEmitter::EmitAdd(const if (Value *FMulAdd = tryEmitFMulAdd(op, CGF, Builder)) return FMulAdd; - return Builder.CreateFAdd(op.LHS, op.RHS, "add"); + Value *V = Builder.CreateFAdd(op.LHS, op.RHS, "add"); + return propagateFMFlags(V, op); } return Builder.CreateAdd(op.LHS, op.RHS, "add"); @@ -2755,7 +2774,8 @@ Value *ScalarExprEmitter::EmitSub(const // Try to form an fmuladd. if (Value *FMulAdd = tryEmitFMulAdd(op, CGF, Builder, true)) return FMulAdd; - return Builder.CreateFSub(op.LHS, op.RHS, "sub"); + Value *V = Builder.CreateFSub(op.LHS, op.RHS, "sub"); + return propagateFMFlags(V, op); } return Builder.CreateSub(op.LHS, op.RHS, "sub"); Added: cfe/trunk/test/CodeGen/ffp-contract-fast-option.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/ffp-contract-fast-option.cpp?rev=299469&view=auto ============================================================================== --- cfe/trunk/test/CodeGen/ffp-contract-fast-option.cpp (added) +++ cfe/trunk/test/CodeGen/ffp-contract-fast-option.cpp Tue Apr 4 16:18:30 2017 @@ -0,0 +1,29 @@ +// RUN: %clang_cc1 -O3 -ffp-contract=fast -triple %itanium_abi_triple -emit-llvm -o - %s | FileCheck %s + +float fp_contract_1(float a, float b, float c) { + // CHECK-LABEL: fp_contract_1fff( + // CHECK: fmul contract float + // CHECK: fadd contract float + return a * b + c; +} + +float fp_contract_2(float a, float b, float c) { + // CHECK-LABEL: fp_contract_2fff( + // CHECK: fmul contract float + // CHECK: fsub contract float + return a * b - c; +} + +void fp_contract_3(float *a, float b, float c) { + // CHECK-LABEL: fp_contract_3Pfff( + // CHECK: fmul contract float + // CHECK: fadd contract float + a[0] += b * c; +} + +void fp_contract_4(float *a, float b, float c) { + // CHECK-LABEL: fp_contract_4Pfff( + // CHECK: fmul contract float + // CHECK: fsub contract float + a[0] -= b * c; +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
