clang/test/Sema/floating-point-compare.c

   1 // RUN: %clang_cc1 -fsyntax-only -Wfloat-equal -verify %s
   2
   3 int f1(float x, float y) {
   4   return x == y; // expected-warning {{comparing floating point with ==}}
   5 }
   6
   7 int f2(float x, float y) {
   8   return x != y; // expected-warning {{comparing floating point with ==}}
   9 }
  10
  11 int f3(float x) {
  12   return x == x; // no-warning
  13 }
  14
  15 // 0.0 can be represented exactly, so don't warn.
  16 int f4(float x) {
  17   return x == 0.0; // no-warning {{comparing}}
  18 }
  19
  20 int f5(float x) {
  21   return x == __builtin_inf(); // no-warning
  22 }
  23
  24 // The literal is a double that can't be represented losslessly as a float.
  25 int tautological_FP_compare(float x) {
  26   return x == 3.14159; // expected-warning {{floating-point comparison is always false}}
  27 }
  28
  29 int tautological_FP_compare_inverse(float x) {
  30   return x != 3.14159; // expected-warning {{floating-point comparison is always true}}
  31 }
  32
  33 // The literal is a double that can be represented losslessly as a long double,
  34 // but this might not be the comparison what was intended.
  35 int not_tautological_FP_compare(long double f) {
  36   return f == 0.1; // expected-warning {{comparing floating point with ==}}
  37 }
  38
  39 int tautological_FP_compare_commute(float f) {
  40   return 0.3 == f; // expected-warning {{floating-point comparison is always false}}
  41 }
  42
  43 int tautological_FP_compare_commute_inverse(float f) {
  44   return 0.3 != f; // expected-warning {{floating-point comparison is always true}}
  45 }
  46
  47 int tautological_FP_compare_explicit_upcast(float f) {
  48   return 0.3 == (double) f; // expected-warning {{floating-point comparison is always false}}
  49 }
  50
  51 int tautological_FP_compare_explicit_downcast(double d) {
  52   return 0.3 == (float) d; // expected-warning {{floating-point comparison is always false}}
  53 }
  54
  55 int tautological_FP_compare_ignore_parens(float f) {
  56   return f == (0.3); // expected-warning {{floating-point comparison is always false}}
  57 }
  58
  59 #define CST 0.3
  60
  61 int tautological_FP_compare_macro(float f) {
  62   return f == CST; // expected-warning {{floating-point comparison is always false}}
  63 }