add FORCE_EVAL macro to evaluate float expr for their side effect
updated nextafter* to use FORCE_EVAL, it can be used in many other
places in the math code to improve readability.
diff --git a/src/internal/libm.h b/src/internal/libm.h
index 8c5474a..a71c4c0 100644
--- a/src/internal/libm.h
+++ b/src/internal/libm.h
@@ -32,6 +32,19 @@
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 { \
diff --git a/src/math/nextafter.c b/src/math/nextafter.c
index e4bfb02..a3b42c9 100644
--- a/src/math/nextafter.c
+++ b/src/math/nextafter.c
@@ -29,9 +29,7 @@
if (e == 0x7ff)
return x + x;
/* raise underflow if ux.value is subnormal or zero */
- if (e == 0) {
- volatile double z;
- z = x*x + ux.value*ux.value;
- }
+ if (e == 0)
+ FORCE_EVAL(x*x + ux.value*ux.value);
return ux.value;
}
diff --git a/src/math/nextafterf.c b/src/math/nextafterf.c
index 47775b9..b703487 100644
--- a/src/math/nextafterf.c
+++ b/src/math/nextafterf.c
@@ -28,9 +28,7 @@
if (e == 0x7f800000)
return x + x;
/* raise underflow if ux.value is subnormal or zero */
- if (e == 0) {
- volatile float z;
- z = x*x + ux.value*ux.value;
- }
+ if (e == 0)
+ FORCE_EVAL(x*x + ux.value*ux.value);
return ux.value;
}
diff --git a/src/math/nextafterl.c b/src/math/nextafterl.c
index c09d9dd..edc3cc9 100644
--- a/src/math/nextafterl.c
+++ b/src/math/nextafterl.c
@@ -38,10 +38,8 @@
if (ux.bits.exp == 0x7fff)
return x + x;
/* raise underflow if ux.value is subnormal or zero */
- if (ux.bits.exp == 0) {
- volatile float z;
- z = x*x + ux.value*ux.value;
- }
+ if (ux.bits.exp == 0)
+ FORCE_EVAL(x*x + ux.value*ux.value);
return ux.value;
}
#elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384
@@ -77,10 +75,8 @@
if (ux.bits.exp == 0x7fff)
return x + x;
/* raise underflow if ux.value is subnormal or zero */
- if (ux.bits.exp == 0) {
- volatile float z;
- z = x*x + ux.value*ux.value;
- }
+ if (ux.bits.exp == 0)
+ FORCE_EVAL(x*x + ux.value*ux.value);
return ux.value;
}
#endif
diff --git a/src/math/nexttoward.c b/src/math/nexttoward.c
index 43f8fee..7355f2f 100644
--- a/src/math/nexttoward.c
+++ b/src/math/nexttoward.c
@@ -38,10 +38,8 @@
if (e == 0x7ff)
return x + x;
/* raise underflow if ux.value is subnormal or zero */
- if (e == 0) {
- volatile float z;
- z = x*x + ux.value*ux.value;
- }
+ if (e == 0)
+ FORCE_EVAL(x*x + ux.value*ux.value);
return ux.value;
}
#endif
diff --git a/src/math/nexttowardf.c b/src/math/nexttowardf.c
index e8e6f67..8648be6 100644
--- a/src/math/nexttowardf.c
+++ b/src/math/nexttowardf.c
@@ -30,9 +30,7 @@
if (e == 0x7f800000)
return x + x;
/* raise underflow if ux.value is subnormal or zero */
- if (e == 0) {
- volatile float z;
- z = x*x + ux.value*ux.value;
- }
+ if (e == 0)
+ FORCE_EVAL(x*x + ux.value*ux.value);
return ux.value;
}
