[src/trunk]: src/lib/libm/noieee_src Avoid strict aliasing problems

[martin <martin%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/fedea155925f
branches:  trunk
changeset: 794758:fedea155925f
user:      martin <martin%NetBSD.org@localhost>
date:      Sun Mar 23 15:26:47 2014 +0000

description:
Avoid strict aliasing problems

diffstat:

 lib/libm/noieee_src/n_exp2.c  |  17 ++++++++++-------
 lib/libm/noieee_src/n_exp2f.c |  16 +++++++++-------
 2 files changed, 19 insertions(+), 14 deletions(-)

diffs (104 lines):

diff -r 1e213a578fc6 -r fedea155925f lib/libm/noieee_src/n_exp2.c
--- a/lib/libm/noieee_src/n_exp2.c      Sun Mar 23 15:21:15 2014 +0000
+++ b/lib/libm/noieee_src/n_exp2.c      Sun Mar 23 15:26:47 2014 +0000
@@ -25,13 +25,14 @@
  */
 
 #include <sys/cdefs.h>
-__RCSID("$NetBSD: n_exp2.c,v 1.2 2014/03/12 19:42:18 martin Exp $");
+__RCSID("$NetBSD: n_exp2.c,v 1.3 2014/03/23 15:26:47 martin Exp $");
 #ifdef __FBSDID
 __FBSDID("$FreeBSD: src/lib/msun/src/s_exp2.c,v 1.7 2008/02/22 02:27:34 das Exp $");
 #endif
 
 #include <stdint.h>
 #include <float.h>
+#include <string.h>
 
 #include "math.h"
 
@@ -344,11 +345,11 @@
 exp2(double x)
 {
        double r, t, twopk, z;
-       uint32_t hx, ix, i0;
+       uint32_t hx, ix, i0, temp;
        int k, big;
 
        /* Filter out exceptional cases. */
-       hx = ((uint32_t*)&x)[0];
+       memcpy(&hx, &x, sizeof(hx));
        ix = hx & 0x7fffffff;           /* high word of |x| */
        if(ix >= 0x40900000) {                  /* |x| >= 1024 */
                if(x >= 0x1.0p10)
@@ -373,11 +374,13 @@
        z -= tbl[i0 + 1];       /* eps[i0]   */
        big = k >= -1021 << 20;
        if (big) {
-               ((uint32_t*)&twopk)[0] = 0x3ff00000+k;
-               ((uint32_t*)&twopk)[1] = 0;
+               temp = 0x3ff00000+k;
+               twopk = 0.0;
+               memcpy(&twopk, &temp, sizeof(temp));
        } else {
-               ((uint32_t*)&twopk)[0] = 0x3ff00000+k + (1000 << 20);
-               ((uint32_t*)&twopk)[1] = 0;
+               temp =  0x3ff00000+k + (1000 << 20);
+               twopk = 0.0;
+               memcpy(&twopk, &temp, sizeof(temp));
        }
        r = t + t * z * (P1 + z * (P2 + z * (P3 + z * (P4 + z * P5))));
 
diff -r 1e213a578fc6 -r fedea155925f lib/libm/noieee_src/n_exp2f.c
--- a/lib/libm/noieee_src/n_exp2f.c     Sun Mar 23 15:21:15 2014 +0000
+++ b/lib/libm/noieee_src/n_exp2f.c     Sun Mar 23 15:26:47 2014 +0000
@@ -25,13 +25,14 @@
  */
 
 #include <sys/cdefs.h>
-__RCSID("$NetBSD: n_exp2f.c,v 1.1 2014/03/06 10:55:57 martin Exp $");
+__RCSID("$NetBSD: n_exp2f.c,v 1.2 2014/03/23 15:26:47 martin Exp $");
 #ifdef __FBSDID
 __FBSDID("$FreeBSD: src/lib/msun/src/s_exp2f.c,v 1.9 2008/02/22 02:27:34 das Exp $");
 #endif
 
 #include <stdint.h>
 #include <float.h>
+#include <string.h>
 
 #include "math.h"
 
@@ -99,10 +100,10 @@
        double tv, twopk, u, z;
        float t;
        uint32_t hx, ix, i0;
-       int32_t k;
+       int32_t k, temp;
 
        /* Filter out exceptional cases. */
-       hx = *((uint32_t*)&x);
+       memcpy(&hx, &x, sizeof(hx));
        ix = hx & 0x7fffffff;           /* high word of |x| */
        if(ix >= 0x43000000) {                  /* |x| >= 128 */
                if(x >= 0x1.0p7f)
@@ -114,15 +115,16 @@
        }
 
        /* Reduce x, computing z, i0, and k. */
-       *((volatile float*)&t) = x + redux;
-       i0 = *((uint32_t*)&t);
+       i0 = x + redux;
+       memcpy(&t, &i0, sizeof(t));
        i0 += TBLSIZE / 2;
        k = (i0 >> TBLBITS) << 20;
        i0 &= TBLSIZE - 1;
        t -= redux;
        z = x - t;
-       ((uint32_t*)&twopk)[0] = 0x3ff00000+k;
-       ((uint32_t*)&twopk)[1] = 0;
+       temp = 0x3ff00000+k;
+       twopk = 0.0;
+       memcpy(&twopk, &temp, sizeof(temp));
 
        /* Compute r = exp2(y) = exp2ft[i0] * p(z). */
        tv = exp2ft[i0];