clang/test/CodeGen/fp-reassoc-pragma.cpp

   1 // RUN: %clang_cc1 -O3 -triple %itanium_abi_triple -emit-llvm -o - %s | FileCheck %s
   2 // Simple case
   3 float fp_reassoc_simple(float a, float b, float c) {
   4 // CHECK: _Z17fp_reassoc_simplefff
   5 // CHECK: %[[A:.+]] = fadd reassoc float %b, %c
   6 // CHECK: %[[M:.+]] = fmul reassoc float %b, %[[A]]
   7 // CHECK-NEXT: fadd reassoc float %c, %[[M]]
   8 #pragma clang fp reassociate(on)
   9   a = b + c;
  10   return a * b + c;
  11 }
  12
  13 // Reassoc pragma should only apply to its scope
  14 float fp_reassoc_scoped(float a, float b, float c) {
  15   // CHECK: _Z17fp_reassoc_scopedfff
  16   // CHECK: %[[M:.+]] = fmul float %a, %b
  17   // CHECK-NEXT: fadd float %[[M]], %c
  18   {
  19 #pragma clang fp reassociate(on)
  20   }
  21   return a * b + c;
  22 }
  23
  24 // Reassoc pragma should apply to templates as well
  25 class Foo {};
  26 Foo operator+(Foo, Foo);
  27 template <typename T>
  28 T template_reassoc(T a, T b, T c) {
  29 #pragma clang fp reassociate(on)
  30   return ((a + b) - c) + c;
  31 }
  32
  33 float fp_reassoc_template(float a, float b, float c) {
  34   // CHECK: _Z19fp_reassoc_templatefff
  35   // CHECK: %[[A1:.+]] = fadd reassoc float %a, %b
  36   // CHECK-NEXT: %[[A2:.+]] = fsub reassoc float %[[A1]], %c
  37   // CHECK-NEXT: fadd reassoc float %c, %[[A2]]
  38   return template_reassoc<float>(a, b, c);
  39 }
  40
  41 // File Scoping should work across functions
  42 #pragma clang fp reassociate(on)
  43 float fp_file_scope_on(float a, float b, float c) {
  44   // CHECK: _Z16fp_file_scope_onfff
  45   // CHECK: %[[M1:.+]] = fmul reassoc float %a, %c
  46   // CHECK-NEXT: %[[M2:.+]] = fmul reassoc float %b, %c
  47   // CHECK-NEXT: fadd reassoc float %[[M1]], %[[M2]]
  48   return (a * c) + (b * c);
  49 }
  50
  51 // Inner pragma has precedence
  52 float fp_file_scope_stop(float a, float b, float c) {
  53   // CHECK: _Z18fp_file_scope_stopfff
  54   // CHECK: %[[A:.+]] = fadd reassoc float %a, %a
  55   // CHECK: %[[M1:.+]] = fmul float %[[A]], %c
  56   // CHECK-NEXT: %[[M2:.+]] = fmul float %b, %c
  57   // CHECK-NEXT: fsub float %[[M1]], %[[M2]]
  58   a = a + a;
  59   {
  60 #pragma clang fp reassociate(off)
  61     return (a * c) - (b * c);
  62   }
  63 }
  64
  65 #pragma clang fp reassociate(off)
  66 float fp_reassoc_off(float a, float b, float c) {
  67   // CHECK: _Z14fp_reassoc_offfff
  68   // CHECK: %[[D1:.+]] = fdiv float %a, %c
  69   // CHECK-NEXT: %[[D2:.+]] = fdiv float %b, %c
  70   // CHECK-NEXT: fadd float %[[D1]], %[[D2]]
  71   return (a / c) + (b / c);
  72 }
  73
  74 // Takes latest flag
  75 float fp_reassoc_many(float a, float b, float c) {
  76 // CHECK: _Z15fp_reassoc_manyfff
  77 // CHECK: %[[D1:.+]] = fdiv reassoc float %a, %c
  78 // CHECK-NEXT: %[[D2:.+]] = fdiv reassoc float %b, %c
  79 // CHECK-NEXT: fadd reassoc float %[[D1]], %[[D2]]
  80 #pragma clang fp reassociate(off) reassociate(on)
  81   return (a / c) + (b / c);
  82 }
  83
  84 // Pragma does not propagate through called functions
  85 float helper_func(float a, float b, float c) { return a + b + c; }
  86 float fp_reassoc_call_helper(float a, float b, float c) {
  87 // CHECK: _Z22fp_reassoc_call_helperfff
  88 // CHECK: %[[S1:.+]] = fadd float %a, %b
  89 // CHECK-NEXT: fadd float %[[S1]], %c
  90 #pragma clang fp reassociate(on)
  91   return helper_func(a, b, c);
  92 }