add FORCE_EVAL macro to evaluate float expr for their side effect

[musl] / src / internal / libm.h

diff --git a/src/internal/libm.h b/src/internal/libm.h
index 8c5474a..a71c4c0 100644 (file)
--- a/src/internal/libm.h
+++ b/src/internal/libm.h
@@ -32,6 +32,19 @@ union dshape {
        uint64_t bits;
 };
 
+#define FORCE_EVAL(x) do {                          \
+       if (sizeof(x) == sizeof(float)) {           \
+               volatile float __x;                 \
+               __x = (x);                          \
+       } else if (sizeof(x) == sizeof(double)) {   \
+               volatile double __x;                \
+               __x = (x);                          \
+       } else {                                    \
+               volatile long double __x;           \
+               __x = (x);                          \
+       }                                           \
+} while(0)
+
 /* Get two 32 bit ints from a double.  */
 #define EXTRACT_WORDS(hi,lo,d)                                  \
 do {                                                            \