test/CodeGen/fp-contract-pragma.cpp

// RUN: %clang_cc1 -O3 -emit-llvm -o - %s | FileCheck %s

// Is FP_CONTRACT is honored in a simple case?
float fp_contract_1(float a, float b, float c) {
// CHECK: _Z13fp_contract_1fff
// CHECK-NEXT: entry
// CHECK-NEXT: %0 = tail call float @llvm.fmuladd
  #pragma STDC FP_CONTRACT ON
  return a * b + c;
}

// Is FP_CONTRACT state cleared on exiting compound statements?
float fp_contract_2(float a, float b, float c) {
// CHECK: _Z13fp_contract_2fff
// CHECK-NEXT: entry
// CHECK-NEXT: %mul = fmul float %a, %b
// CHECK-NEXT: %add = fadd float %mul, %c
  {
    #pragma STDC FP_CONTRACT ON
  }
  return a * b + c;  
}

// Does FP_CONTRACT survive template instatiation?
class Foo {};
Foo operator+(Foo, Foo);

template <typename T>
T template_muladd(T a, T b, T c) {
  #pragma STDC FP_CONTRACT ON
  return a * b + c;
}

float fp_contract_3(float a, float b, float c) {
// CHECK: _Z13fp_contract_3fff
// CHECK-NEXT: entry
// CHECK-NEXT: %0 = tail call float @llvm.fmuladd
  return template_muladd<float>(a, b, c);
}