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 (file)
--- a/src/internal/libm.h
+++ b/src/internal/libm.h
@@ -32,6 +32,19 @@ union dshape {
        uint64_t bits;
 };
 
        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 {                                                            \
 /* 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 (file)
--- a/src/math/nextafter.c
+++ b/src/math/nextafter.c
@@ -29,9 +29,7 @@ double nextafter(double x, double y)
        if (e == 0x7ff)
                return x + x;
        /* raise underflow if ux.value is subnormal or zero */
        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;
 }
        return ux.value;
 }

diff --git a/src/math/nextafterf.c b/src/math/nextafterf.c
index 47775b9..b703487 100644 (file)
--- a/src/math/nextafterf.c
+++ b/src/math/nextafterf.c
@@ -28,9 +28,7 @@ float nextafterf(float x, float y)
        if (e == 0x7f800000)
                return x + x;
        /* raise underflow if ux.value is subnormal or zero */
        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;
 }
        return ux.value;
 }

diff --git a/src/math/nextafterl.c b/src/math/nextafterl.c
index c09d9dd..edc3cc9 100644 (file)
--- a/src/math/nextafterl.c
+++ b/src/math/nextafterl.c
@@ -38,10 +38,8 @@ long double nextafterl(long double x, long double y)
        if (ux.bits.exp == 0x7fff)
                return x + x;
        /* raise underflow if ux.value is subnormal or zero */
        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
        return ux.value;
 }
 #elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384


@@ -77,10 +75,8 @@ long double nextafterl(long double x, long double y)
        if (ux.bits.exp == 0x7fff)
                return x + x;
        /* raise underflow if ux.value is subnormal or zero */
        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
        return ux.value;
 }
 #endif

diff --git a/src/math/nexttoward.c b/src/math/nexttoward.c
index 43f8fee..7355f2f 100644 (file)
--- a/src/math/nexttoward.c
+++ b/src/math/nexttoward.c
@@ -38,10 +38,8 @@ double nexttoward(double x, long double y)
        if (e == 0x7ff)
                return x + x;
        /* raise underflow if ux.value is subnormal or zero */
        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
        return ux.value;
 }
 #endif

diff --git a/src/math/nexttowardf.c b/src/math/nexttowardf.c
index e8e6f67..8648be6 100644 (file)
--- a/src/math/nexttowardf.c
+++ b/src/math/nexttowardf.c
@@ -30,9 +30,7 @@ float nexttowardf(float x, long double y)
        if (e == 0x7f800000)
                return x + x;
        /* raise underflow if ux.value is subnormal or zero */
        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;
 }
        return ux.value;
 }