glibc/sysdeps/ieee754/flt-32/e_lgammaf_r.c
Joseph Myers 9124ccf76a Fix lgamma implementations for -Wuninitialized.
If you remove the "override CFLAGS += -Wno-uninitialized" in
math/Makefile, you get errors from lgamma implementations of the form:

../sysdeps/ieee754/dbl-64/e_lgamma_r.c: In function '__ieee754_lgamma_r':
../sysdeps/ieee754/dbl-64/e_lgamma_r.c:297:13: error: 'nadj' may be used uninitialized in this function [-Werror=maybe-uninitialized]
  if(hx<0) r = nadj - r;

This is one of the standard kinds of false positive uninitialized
warnings: nadj is set under a certain condition, and then later used
under the same condition.  This patch uses DIAG_* macros to suppress
the warning on the use of nadj.  The ldbl-128 / ldbl-128ibm
implementation has a substantially different structure that avoids
this issue.

Tested for x86_64.  (In fact this patch eliminates the need for that
-Wno-uninitialized on x86_64, but I want to test on more architectures
before removing it.)

	* sysdeps/ieee754/dbl-64/e_lgamma_r.c: Include <libc-internal.h>.
	(__ieee754_lgamma_r): Ignore uninitialized warnings around use of
	NADJ.
	* sysdeps/ieee754/flt-32/e_lgammaf_r.c: Include <libc-internal.h>.
	(__ieee754_lgammaf_r): Ignore uninitialized warnings around use of
	NADJ.
	* sysdeps/ieee754/ldbl-96/e_lgammal_r.c: Include <libc-internal.h>.
	(__ieee754_lgammal_r): Ignore uninitialized warnings around use of
	NADJ.
2015-05-21 23:44:33 +00:00

248 lines
7.5 KiB
C

/* e_lgammaf_r.c -- float version of e_lgamma_r.c.
* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
*/
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
#include <libc-internal.h>
#include <math.h>
#include <math_private.h>
static const float
two23= 8.3886080000e+06, /* 0x4b000000 */
half= 5.0000000000e-01, /* 0x3f000000 */
one = 1.0000000000e+00, /* 0x3f800000 */
pi = 3.1415927410e+00, /* 0x40490fdb */
a0 = 7.7215664089e-02, /* 0x3d9e233f */
a1 = 3.2246702909e-01, /* 0x3ea51a66 */
a2 = 6.7352302372e-02, /* 0x3d89f001 */
a3 = 2.0580807701e-02, /* 0x3ca89915 */
a4 = 7.3855509982e-03, /* 0x3bf2027e */
a5 = 2.8905137442e-03, /* 0x3b3d6ec6 */
a6 = 1.1927076848e-03, /* 0x3a9c54a1 */
a7 = 5.1006977446e-04, /* 0x3a05b634 */
a8 = 2.2086278477e-04, /* 0x39679767 */
a9 = 1.0801156895e-04, /* 0x38e28445 */
a10 = 2.5214456400e-05, /* 0x37d383a2 */
a11 = 4.4864096708e-05, /* 0x383c2c75 */
tc = 1.4616321325e+00, /* 0x3fbb16c3 */
tf = -1.2148628384e-01, /* 0xbdf8cdcd */
/* tt = -(tail of tf) */
tt = 6.6971006518e-09, /* 0x31e61c52 */
t0 = 4.8383611441e-01, /* 0x3ef7b95e */
t1 = -1.4758771658e-01, /* 0xbe17213c */
t2 = 6.4624942839e-02, /* 0x3d845a15 */
t3 = -3.2788541168e-02, /* 0xbd064d47 */
t4 = 1.7970675603e-02, /* 0x3c93373d */
t5 = -1.0314224288e-02, /* 0xbc28fcfe */
t6 = 6.1005386524e-03, /* 0x3bc7e707 */
t7 = -3.6845202558e-03, /* 0xbb7177fe */
t8 = 2.2596477065e-03, /* 0x3b141699 */
t9 = -1.4034647029e-03, /* 0xbab7f476 */
t10 = 8.8108185446e-04, /* 0x3a66f867 */
t11 = -5.3859531181e-04, /* 0xba0d3085 */
t12 = 3.1563205994e-04, /* 0x39a57b6b */
t13 = -3.1275415677e-04, /* 0xb9a3f927 */
t14 = 3.3552918467e-04, /* 0x39afe9f7 */
u0 = -7.7215664089e-02, /* 0xbd9e233f */
u1 = 6.3282704353e-01, /* 0x3f2200f4 */
u2 = 1.4549225569e+00, /* 0x3fba3ae7 */
u3 = 9.7771751881e-01, /* 0x3f7a4bb2 */
u4 = 2.2896373272e-01, /* 0x3e6a7578 */
u5 = 1.3381091878e-02, /* 0x3c5b3c5e */
v1 = 2.4559779167e+00, /* 0x401d2ebe */
v2 = 2.1284897327e+00, /* 0x4008392d */
v3 = 7.6928514242e-01, /* 0x3f44efdf */
v4 = 1.0422264785e-01, /* 0x3dd572af */
v5 = 3.2170924824e-03, /* 0x3b52d5db */
s0 = -7.7215664089e-02, /* 0xbd9e233f */
s1 = 2.1498242021e-01, /* 0x3e5c245a */
s2 = 3.2577878237e-01, /* 0x3ea6cc7a */
s3 = 1.4635047317e-01, /* 0x3e15dce6 */
s4 = 2.6642270386e-02, /* 0x3cda40e4 */
s5 = 1.8402845599e-03, /* 0x3af135b4 */
s6 = 3.1947532989e-05, /* 0x3805ff67 */
r1 = 1.3920053244e+00, /* 0x3fb22d3b */
r2 = 7.2193557024e-01, /* 0x3f38d0c5 */
r3 = 1.7193385959e-01, /* 0x3e300f6e */
r4 = 1.8645919859e-02, /* 0x3c98bf54 */
r5 = 7.7794247773e-04, /* 0x3a4beed6 */
r6 = 7.3266842264e-06, /* 0x36f5d7bd */
w0 = 4.1893854737e-01, /* 0x3ed67f1d */
w1 = 8.3333335817e-02, /* 0x3daaaaab */
w2 = -2.7777778450e-03, /* 0xbb360b61 */
w3 = 7.9365057172e-04, /* 0x3a500cfd */
w4 = -5.9518753551e-04, /* 0xba1c065c */
w5 = 8.3633989561e-04, /* 0x3a5b3dd2 */
w6 = -1.6309292987e-03; /* 0xbad5c4e8 */
static const float zero= 0.0000000000e+00;
static float
sin_pif(float x)
{
float y,z;
int n,ix;
GET_FLOAT_WORD(ix,x);
ix &= 0x7fffffff;
if(ix<0x3e800000) return __kernel_sinf(pi*x,zero,0);
y = -x; /* x is assume negative */
/*
* argument reduction, make sure inexact flag not raised if input
* is an integer
*/
z = __floorf(y);
if(z!=y) { /* inexact anyway */
y *= (float)0.5;
y = (float)2.0*(y - __floorf(y)); /* y = |x| mod 2.0 */
n = (int) (y*(float)4.0);
} else {
if(ix>=0x4b800000) {
y = zero; n = 0; /* y must be even */
} else {
if(ix<0x4b000000) z = y+two23; /* exact */
GET_FLOAT_WORD(n,z);
n &= 1;
y = n;
n<<= 2;
}
}
switch (n) {
case 0: y = __kernel_sinf(pi*y,zero,0); break;
case 1:
case 2: y = __kernel_cosf(pi*((float)0.5-y),zero); break;
case 3:
case 4: y = __kernel_sinf(pi*(one-y),zero,0); break;
case 5:
case 6: y = -__kernel_cosf(pi*(y-(float)1.5),zero); break;
default: y = __kernel_sinf(pi*(y-(float)2.0),zero,0); break;
}
return -y;
}
float
__ieee754_lgammaf_r(float x, int *signgamp)
{
float t,y,z,nadj,p,p1,p2,p3,q,r,w;
int i,hx,ix;
GET_FLOAT_WORD(hx,x);
/* purge off +-inf, NaN, +-0, and negative arguments */
*signgamp = 1;
ix = hx&0x7fffffff;
if(__builtin_expect(ix>=0x7f800000, 0)) return x*x;
if(__builtin_expect(ix==0, 0))
{
if (hx < 0)
*signgamp = -1;
return one/fabsf(x);
}
if(__builtin_expect(ix<0x30800000, 0)) {
/* |x|<2**-30, return -log(|x|) */
if(hx<0) {
*signgamp = -1;
return -__ieee754_logf(-x);
} else return -__ieee754_logf(x);
}
if(hx<0) {
if(ix>=0x4b000000) /* |x|>=2**23, must be -integer */
return x/zero;
t = sin_pif(x);
if(t==zero) return one/fabsf(t); /* -integer */
nadj = __ieee754_logf(pi/fabsf(t*x));
if(t<zero) *signgamp = -1;
x = -x;
}
/* purge off 1 and 2 */
if (ix==0x3f800000||ix==0x40000000) r = 0;
/* for x < 2.0 */
else if(ix<0x40000000) {
if(ix<=0x3f666666) { /* lgamma(x) = lgamma(x+1)-log(x) */
r = -__ieee754_logf(x);
if(ix>=0x3f3b4a20) {y = one-x; i= 0;}
else if(ix>=0x3e6d3308) {y= x-(tc-one); i=1;}
else {y = x; i=2;}
} else {
r = zero;
if(ix>=0x3fdda618) {y=(float)2.0-x;i=0;} /* [1.7316,2] */
else if(ix>=0x3F9da620) {y=x-tc;i=1;} /* [1.23,1.73] */
else {y=x-one;i=2;}
}
switch(i) {
case 0:
z = y*y;
p1 = a0+z*(a2+z*(a4+z*(a6+z*(a8+z*a10))));
p2 = z*(a1+z*(a3+z*(a5+z*(a7+z*(a9+z*a11)))));
p = y*p1+p2;
r += (p-(float)0.5*y); break;
case 1:
z = y*y;
w = z*y;
p1 = t0+w*(t3+w*(t6+w*(t9 +w*t12))); /* parallel comp */
p2 = t1+w*(t4+w*(t7+w*(t10+w*t13)));
p3 = t2+w*(t5+w*(t8+w*(t11+w*t14)));
p = z*p1-(tt-w*(p2+y*p3));
r += (tf + p); break;
case 2:
p1 = y*(u0+y*(u1+y*(u2+y*(u3+y*(u4+y*u5)))));
p2 = one+y*(v1+y*(v2+y*(v3+y*(v4+y*v5))));
r += (-(float)0.5*y + p1/p2);
}
}
else if(ix<0x41000000) { /* x < 8.0 */
i = (int)x;
t = zero;
y = x-(float)i;
p = y*(s0+y*(s1+y*(s2+y*(s3+y*(s4+y*(s5+y*s6))))));
q = one+y*(r1+y*(r2+y*(r3+y*(r4+y*(r5+y*r6)))));
r = half*y+p/q;
z = one; /* lgamma(1+s) = log(s) + lgamma(s) */
switch(i) {
case 7: z *= (y+(float)6.0); /* FALLTHRU */
case 6: z *= (y+(float)5.0); /* FALLTHRU */
case 5: z *= (y+(float)4.0); /* FALLTHRU */
case 4: z *= (y+(float)3.0); /* FALLTHRU */
case 3: z *= (y+(float)2.0); /* FALLTHRU */
r += __ieee754_logf(z); break;
}
/* 8.0 <= x < 2**26 */
} else if (ix < 0x4c800000) {
t = __ieee754_logf(x);
z = one/x;
y = z*z;
w = w0+z*(w1+y*(w2+y*(w3+y*(w4+y*(w5+y*w6)))));
r = (x-half)*(t-one)+w;
} else
/* 2**26 <= x <= inf */
r = x*(__ieee754_logf(x)-one);
/* NADJ is set for negative arguments but not otherwise,
resulting in warnings that it may be used uninitialized
although in the cases where it is used it has always been
set. */
DIAG_PUSH_NEEDS_COMMENT;
#if __GNUC_PREREQ (4, 7)
DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wmaybe-uninitialized");
#else
DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wuninitialized");
#endif
if(hx<0) r = nadj - r;
DIAG_POP_NEEDS_COMMENT;
return r;
}
strong_alias (__ieee754_lgammaf_r, __lgammaf_r_finite)