math: remove *_WORD64 macros from libm.h

only fma used these macros and the explicit union is clearer

src/internal/libm.h

@@ -80,14 +80,6 @@ do {                                                            \
   (lo) = (uint32_t)__u.bits;                                    \
 } while (0)
 
-/* Get a 64 bit int from a double.  */
-#define EXTRACT_WORD64(i,d)                                     \
-do {                                                            \
-  union dshape __u;                                             \
-  __u.value = (d);                                              \
-  (i) = __u.bits;                                               \
-} while (0)
-
 /* Get the more significant 32 bit int from a double.  */
 #define GET_HIGH_WORD(i,d)                                      \
 do {                                                            \
@@ -112,14 +104,6 @@ do {                                                            \
   (d) = __u.value;                                              \
 } while (0)
 
-/* Set a double from a 64 bit int.  */
-#define INSERT_WORD64(d,i)                                      \
-do {                                                            \
-  union dshape __u;                                             \
-  __u.bits = (i);                                               \
-  (d) = __u.value;                                              \
-} while (0)
-
 /* Set the more significant 32 bits of a double from an int.  */
 #define SET_HIGH_WORD(d,hi)                                     \
 do {                                                            \

src/math/fma.c

@@ -232,16 +232,16 @@ static inline struct dd dd_add(double a, double b)
 static inline double add_adjusted(double a, double b)
 {
 	struct dd sum;
-	uint64_t hibits, lobits;
+	union {double f; uint64_t i;} uhi, ulo;
 
 	sum = dd_add(a, b);
 	if (sum.lo != 0) {
-		EXTRACT_WORD64(hibits, sum.hi);
-		if ((hibits & 1) == 0) {
+		uhi.f = sum.hi;
+		if ((uhi.i & 1) == 0) {
 			/* hibits += (int)copysign(1.0, sum.hi * sum.lo) */
-			EXTRACT_WORD64(lobits, sum.lo);
-			hibits += 1 - ((hibits ^ lobits) >> 62);
-			INSERT_WORD64(sum.hi, hibits);
+			ulo.f = sum.lo;
+			uhi.i += 1 - ((uhi.i ^ ulo.i) >> 62);
+			sum.hi = uhi.f;
 		}
 	}
 	return (sum.hi);
@@ -255,7 +255,7 @@ static inline double add_adjusted(double a, double b)
 static inline double add_and_denormalize(double a, double b, int scale)
 {
 	struct dd sum;
-	uint64_t hibits, lobits;
+	union {double f; uint64_t i;} uhi, ulo;
 	int bits_lost;
 
 	sum = dd_add(a, b);
@@ -271,13 +271,13 @@ static inline double add_and_denormalize(double a, double b, int scale)
 	 * break the ties manually.
 	 */
 	if (sum.lo != 0) {
-		EXTRACT_WORD64(hibits, sum.hi);
-		bits_lost = -((int)(hibits >> 52) & 0x7ff) - scale + 1;
-		if (bits_lost != 1 ^ (int)(hibits & 1)) {
+		uhi.f = sum.hi;
+		bits_lost = -((int)(uhi.i >> 52) & 0x7ff) - scale + 1;
+		if (bits_lost != 1 ^ (int)(uhi.i & 1)) {
 			/* hibits += (int)copysign(1.0, sum.hi * sum.lo) */
-			EXTRACT_WORD64(lobits, sum.lo);
-			hibits += 1 - (((hibits ^ lobits) >> 62) & 2);
-			INSERT_WORD64(sum.hi, hibits);
+			ulo.f = sum.lo;
+			uhi.i += 1 - (((uhi.i ^ ulo.i) >> 62) & 2);
+			sum.hi = uhi.f;
 		}
 	}
 	return scalbn(sum.hi, scale);