From 9b7f6f2de89a321f7eae5e942c8668cb50acfd1d Mon Sep 17 00:00:00 2001 From: Shuxin Yang Date: Thu, 29 Nov 2012 01:47:31 +0000 Subject: [PATCH] Instruction::isAssociative() returns true for fmul/fadd if they are tagged "unsafe" mode. Approved by: Eli and Michael. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168848 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/Instruction.h | 2 +- lib/VMCore/Instruction.cpp | 14 +++++++++++ test/Transforms/InstCombine/fast-math.ll | 32 ++++++++++++++++++++++++ 3 files changed, 47 insertions(+), 1 deletion(-) create mode 100644 test/Transforms/InstCombine/fast-math.ll diff --git a/include/llvm/Instruction.h b/include/llvm/Instruction.h index 22c8289c73ae..2c1d41c705b9 100644 --- a/include/llvm/Instruction.h +++ b/include/llvm/Instruction.h @@ -253,7 +253,7 @@ class Instruction : public User, public ilist_node { /// /// In LLVM, the Add, Mul, And, Or, and Xor operators are associative. /// - bool isAssociative() const { return isAssociative(getOpcode()); } + bool isAssociative() const; static bool isAssociative(unsigned op); /// isCommutative - Return true if the instruction is commutative: diff --git a/lib/VMCore/Instruction.cpp b/lib/VMCore/Instruction.cpp index 4208144cb5b5..d93c1d7a22c0 100644 --- a/lib/VMCore/Instruction.cpp +++ b/lib/VMCore/Instruction.cpp @@ -468,6 +468,20 @@ bool Instruction::isAssociative(unsigned Opcode) { Opcode == Add || Opcode == Mul; } +bool Instruction::isAssociative() const { + unsigned Opcode = getOpcode(); + if (isAssociative(Opcode)) + return true; + + switch (Opcode) { + case FMul: + case FAdd: + return cast(this)->hasUnsafeAlgebra(); + default: + return false; + } +} + /// isCommutative - Return true if the instruction is commutative: /// /// Commutative operators satisfy: (x op y) === (y op x) diff --git a/test/Transforms/InstCombine/fast-math.ll b/test/Transforms/InstCombine/fast-math.ll new file mode 100644 index 000000000000..42241409ff89 --- /dev/null +++ b/test/Transforms/InstCombine/fast-math.ll @@ -0,0 +1,32 @@ +; RUN: opt < %s -instcombine -S | FileCheck %s + +; testing-case "float fold(float a) { return 1.2f * a * 2.3f; }" +; 1.2f and 2.3f is supposed to be fold. +define float @fold(float %a) { +fold: + %mul = fmul fast float %a, 0x3FF3333340000000 + %mul1 = fmul fast float %mul, 0x4002666660000000 + ret float %mul1 +; CHECK: fold +; CHECK: fmul float %a, 0x4006147AE0000000 +} + +; Same testing-case as the one used in fold() except that the operators have +; fixed FP mode. +define float @notfold(float %a) { +notfold: +; CHECK: notfold +; CHECK: %mul = fmul fast float %a, 0x3FF3333340000000 + %mul = fmul fast float %a, 0x3FF3333340000000 + %mul1 = fmul float %mul, 0x4002666660000000 + ret float %mul1 +} + +define float @fold2(float %a) { +notfold2: +; CHECK: fold2 +; CHECK: fmul float %a, 0x4006147AE0000000 + %mul = fmul float %a, 0x3FF3333340000000 + %mul1 = fmul fast float %mul, 0x4002666660000000 + ret float %mul1 +}