fix double-processing of DT_RELR relocations in ldso relocating itself

[musl] / src / math / __rem_pio2f.c

diff --git a/src/math/__rem_pio2f.c b/src/math/__rem_pio2f.c
index 5bdeb52..e676564 100644 (file)
--- a/src/math/__rem_pio2f.c
+++ b/src/math/__rem_pio2f.c
@@ -22,54 +22,62 @@
 
 #include "libm.h"
 
+#if FLT_EVAL_METHOD==0 || FLT_EVAL_METHOD==1
+#define EPS DBL_EPSILON
+#elif FLT_EVAL_METHOD==2
+#define EPS LDBL_EPSILON
+#endif
+
 /*
  * invpio2:  53 bits of 2/pi
  * pio2_1:   first 25 bits of pi/2
  * pio2_1t:  pi/2 - pio2_1
  */
 static const double
+toint   = 1.5/EPS,
+pio4    = 0x1.921fb6p-1,
 invpio2 = 6.36619772367581382433e-01, /* 0x3FE45F30, 0x6DC9C883 */
 pio2_1  = 1.57079631090164184570e+00, /* 0x3FF921FB, 0x50000000 */
 pio2_1t = 1.58932547735281966916e-08; /* 0x3E5110b4, 0x611A6263 */
 
 int __rem_pio2f(float x, double *y)
 {
-       double w,r,fn;
+       union {float f; uint32_t i;} u = {x};
        double tx[1],ty[1];
-       float z;
-       int32_t e0,n,ix,hx;
+       double_t fn;
+       uint32_t ix;
+       int n, sign, e0;
 
-       GET_FLOAT_WORD(hx, x);
-       ix = hx & 0x7fffffff;
+       ix = u.i & 0x7fffffff;
        /* 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. */
-               fn = x*invpio2 + 0x1.8p52;
-               fn = fn - 0x1.8p52;
-// FIXME
-#ifdef HAVE_EFFICIENT_IRINT
-               n  = irint(fn);
-#else
+               /* Use a specialized rint() to get fn. */
+               fn = (double_t)x*invpio2 + toint - toint;
                n  = (int32_t)fn;
-#endif
-               r  = x - fn*pio2_1;
-               w  = fn*pio2_1t;
-               *y = r - w;
+               *y = x - fn*pio2_1 - fn*pio2_1t;
+               /* Matters with directed rounding. */
+               if (predict_false(*y < -pio4)) {
+                       n--;
+                       fn--;
+                       *y = x - fn*pio2_1 - fn*pio2_1t;
+               } else if (predict_false(*y > pio4)) {
+                       n++;
+                       fn++;
+                       *y = x - fn*pio2_1 - fn*pio2_1t;
+               }
                return n;
        }
-       /*
-        * all other (large) arguments
-        */
        if(ix>=0x7f800000) {  /* x is inf or NaN */
                *y = x-x;
                return 0;
        }
-       /* set z = scalbn(|x|,ilogb(|x|)-23) */
-       e0 = (ix>>23) - 150;  /* e0 = ilogb(|x|)-23; */
-       SET_FLOAT_WORD(z, ix - ((int32_t)(e0<<23)));
-       tx[0] = z;
+       /* scale x into [2^23, 2^24-1] */
+       sign = u.i>>31;
+       e0 = (ix>>23) - (0x7f+23);  /* e0 = ilogb(|x|)-23, positive */
+       u.i = ix - (e0<<23);
+       tx[0] = u.f;
        n  =  __rem_pio2_large(tx,ty,e0,1,0);
-       if (hx < 0) {
+       if (sign) {
                *y = -ty[0];
                return -n;
        }