math: remove STRICT_ASSIGN macro

gcc did not always drop excess precision according to c99 at assignments
before version 4.5 even if -std=c99 was requested which caused badly
broken mathematical functions on i386 when FLT_EVAL_METHOD!=0

but STRICT_ASSIGN was not used consistently and it is worked around for
old compilers with -ffloat-store so it is no longer needed

the new convention is to get the compiler respect c99 semantics and when
excess precision is not harmful use float_t or double_t or to specialize
code using FLT_EVAL_METHOD

src/internal/libm.h

@@ -155,15 +155,4 @@ long double __tanl(long double, long double, int);
 long double __polevll(long double, const long double *, int);
 long double __p1evll(long double, const long double *, int);
 
-#if 0
-/* Attempt to get strict C99 semantics for assignment with non-C99 compilers. */
-#define STRICT_ASSIGN(type, lval, rval) do {    \
-        volatile type __v = (rval);             \
-        (lval) = __v;                           \
-} while (0)
-#else
-/* Should work with -fexcess-precision=standard (>=gcc-4.5) or -ffloat-store */
-#define STRICT_ASSIGN(type, lval, rval) ((lval) = (type)(rval))
-#endif
-
 #endif

src/math/__rem_pio2.c

@@ -112,7 +112,7 @@ int __rem_pio2(double x, double *y)
 		uint32_t high;
 medium:
 		/* Use a specialized rint() to get fn.  Assume round-to-nearest. */
-		STRICT_ASSIGN(double, fn, x*invpio2 + 0x1.8p52);
+		fn = x*invpio2 + 0x1.8p52;
 		fn = fn - 0x1.8p52;
 // FIXME
 #ifdef HAVE_EFFICIENT_IRINT

src/math/__rem_pio2_large.c

@@ -415,7 +415,8 @@ recompute:
 		fw = 0.0;
 		for (i=jz; i>=0; i--)
 			fw += fq[i];
-		STRICT_ASSIGN(double,fw,fw);
+		// TODO: drop excess precision here once double_t is used
+		fw = (double)fw;
 		y[0] = ih==0 ? fw : -fw;
 		fw = fq[0]-fw;
 		for (i=1; i<=jz; i++)

src/math/__rem_pio2f.c

@@ -44,7 +44,7 @@ int __rem_pio2f(float x, double *y)
 	/* 25+53 bit pi is good enough for medium size */
 	if (ix < 0x4dc90fdb) {  /* |x| ~< 2^28*(pi/2), medium size */
 		/* Use a specialized rint() to get fn.  Assume round-to-nearest. */
-		STRICT_ASSIGN(double, fn, x*invpio2 + 0x1.8p52);
+		fn = x*invpio2 + 0x1.8p52;
 		fn = fn - 0x1.8p52;
 // FIXME
 #ifdef HAVE_EFFICIENT_IRINT

src/math/exp.c

@@ -94,7 +94,7 @@ double exp(double x)
 			return x;
 		if (x > 709.782712893383973096) {
 			/* overflow if x!=inf */
-			STRICT_ASSIGN(double, x, 0x1p1023 * x);
+			x *= 0x1p1023;
 			return x;
 		}
 		if (x < -708.39641853226410622) {
@@ -113,7 +113,7 @@ double exp(double x)
 			k = 1 - sign - sign;
 		hi = x - k*ln2hi;  /* k*ln2hi is exact here */
 		lo = k*ln2lo;
-		STRICT_ASSIGN(double, x, hi - lo);
+		x = hi - lo;
 	} else if (hx > 0x3e300000)  {  /* if |x| > 2**-28 */
 		k = 0;
 		hi = x;

src/math/exp2.c

@@ -340,7 +340,7 @@ double exp2(double x)
 	if (ix >= 0x408ff000) {  /* |x| >= 1022 or nan */
 		if (ix >= 0x40900000 && u.i>>63 == 0) {  /* x >= 1024 or nan */
 			/* overflow */
-			STRICT_ASSIGN(double, x, x * 0x1p1023);
+			x *= 0x1p1023;
 			return x;
 		}
 		if (ix >= 0x7ff00000)  /* -inf or -nan */

src/math/expf.c

@@ -41,7 +41,7 @@ float expf(float x)
 	if (hx >= 0x42aeac50) {  /* if |x| >= -87.33655f or NaN */
 		if (hx >= 0x42b17218 && !sign) {  /* x >= 88.722839f */
 			/* overflow */
-			STRICT_ASSIGN(float, x, x * 0x1p127f);
+			x *= 0x1p127f;
 			return x;
 		}
 		if (sign) {
@@ -60,7 +60,7 @@ float expf(float x)
 			k = 1 - sign - sign;
 		hi = x - k*ln2hi;  /* k*ln2hi is exact here */
 		lo = k*ln2lo;
-		STRICT_ASSIGN(float, x, hi - lo);
+		x = hi - lo;
 	} else if (hx > 0x39000000) {  /* |x| > 2**-14 */
 		k = 0;
 		hi = x;

src/math/expm1.c

@@ -155,7 +155,7 @@ double expm1(double x)
 			hi = x - t*ln2_hi;  /* t*ln2_hi is exact here */
 			lo = t*ln2_lo;
 		}
-		STRICT_ASSIGN(double, x, hi - lo);
+		x = hi-lo;
 		c = (hi-x)-lo;
 	} else if (hx < 0x3c900000) {  /* |x| < 2**-54, return x */
 		if (hx < 0x00100000)

src/math/expm1f.c

@@ -65,7 +65,7 @@ float expm1f(float x)
 			hi = x - t*ln2_hi;      /* t*ln2_hi is exact here */
 			lo = t*ln2_lo;
 		}
-		STRICT_ASSIGN(float, x, hi - lo);
+		x = hi-lo;
 		c = (hi-x)-lo;
 	} else if (hx < 0x33000000) {  /* when |x|<2**-25, return x */
 		if (hx < 0x00800000)

src/math/log1p.c

@@ -122,7 +122,7 @@ double log1p(double x)
 		return x+x;
 	if (k != 0) {
 		if (hx < 0x43400000) {
-			STRICT_ASSIGN(double, u, 1.0 + x);
+			u = 1 + x;
 			GET_HIGH_WORD(hu, u);
 			k = (hu>>20) - 1023;
 			c = k > 0 ? 1.0-(u-x) : x-(u-1.0); /* correction term */

src/math/log1pf.c

@@ -61,7 +61,7 @@ float log1pf(float x)
 		return x+x;
 	if (k != 0) {
 		if (hx < 0x5a000000) {
-			STRICT_ASSIGN(float, u, 1.0f + x);
+			u = 1 + x;
 			GET_FLOAT_WORD(hu, u);
 			k = (hu>>23) - 127;
 			/* correction term */