diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/internal/libm.h | 71 |
1 files changed, 65 insertions, 6 deletions
diff --git a/src/internal/libm.h b/src/internal/libm.h index f7dd9678..5669c046 100644 --- a/src/internal/libm.h +++ b/src/internal/libm.h @@ -5,6 +5,7 @@ #include <float.h> #include <math.h> #include <endian.h> +#include "fp_arch.h" #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024 #elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384 && __BYTE_ORDER == __LITTLE_ENDIAN @@ -58,16 +59,74 @@ union ldshape { #error Unsupported long double representation #endif +/* fp_barrier returns its input, but limits code transformations + as if it had a side-effect (e.g. observable io) and returned + an arbitrary value. */ + +#ifndef fp_barrierf +#define fp_barrierf fp_barrierf +static inline float fp_barrierf(float x) +{ + volatile float y = x; + return y; +} +#endif + +#ifndef fp_barrier +#define fp_barrier fp_barrier +static inline double fp_barrier(double x) +{ + volatile double y = x; + return y; +} +#endif + +#ifndef fp_barrierl +#define fp_barrierl fp_barrierl +static inline long double fp_barrierl(long double x) +{ + volatile long double y = x; + return y; +} +#endif + +/* fp_force_eval ensures that the input value is computed when that's + otherwise unused. To prevent the constant folding of the input + expression, an additional fp_barrier may be needed or a compilation + mode that does so (e.g. -frounding-math in gcc). Then it can be + used to evaluate an expression for its fenv side-effects only. */ + +#ifndef fp_force_evalf +#define fp_force_evalf fp_force_evalf +static inline void fp_force_evalf(float x) +{ + volatile float y = x; +} +#endif + +#ifndef fp_force_eval +#define fp_force_eval fp_force_eval +static inline void fp_force_eval(double x) +{ + volatile double y = x; +} +#endif + +#ifndef fp_force_evall +#define fp_force_evall fp_force_evall +static inline void fp_force_evall(long double x) +{ + volatile long double y = x; +} +#endif + #define FORCE_EVAL(x) do { \ if (sizeof(x) == sizeof(float)) { \ - volatile float __x; \ - __x = (x); \ + fp_force_evalf(x); \ } else if (sizeof(x) == sizeof(double)) { \ - volatile double __x; \ - __x = (x); \ + fp_force_eval(x); \ } else { \ - volatile long double __x; \ - __x = (x); \ + fp_force_evall(x); \ } \ } while(0) |