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Get rid of array-bounds warning in __kernel_rem_pio2[f] with gcc 6.1 -O3.

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On s390x I get the following werror when build with gcc 6.1 (or current gcc head) and -O3:
../sysdeps/ieee754/dbl-64/k_rem_pio2.c: In function ‘__kernel_rem_pio2’:
../sysdeps/ieee754/dbl-64/k_rem_pio2.c:254:18: error: array subscript is below array bounds [-Werror=array-bounds]
    for (k = 1; iq[jk - k] == 0; k++)
                ~~^~~~~~~~
I get the same error with sysdeps/ieee754/flt-32/k_rem_pio2f.c.

This patch adds DIAG_* macros around it.

ChangeLog:

	* sysdeps/ieee754/dbl-64/k_rem_pio2.c (__kernel_rem_pio2):
	Use DIAG_*_NEEDS_COMMENT macro to get rid of array-bounds warning.
	* sysdeps/ieee754/flt-32/k_rem_pio2f.c (__kernel_rem_pio2f):
	Likewise.
This commit is contained in:
Stefan Liebler 2016-08-18 12:20:35 +02:00
parent 2c820533c6
commit b65f0b7b2e
3 changed files with 27 additions and 0 deletions
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7
ChangeLog
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@ -1,3 +1,10 @@
2016-08-18 Stefan Liebler <stli@linux.vnet.ibm.com>
* sysdeps/ieee754/dbl-64/k_rem_pio2.c (__kernel_rem_pio2):
Use DIAG_*_NEEDS_COMMENT macro to get rid of array-bounds warning.
* sysdeps/ieee754/flt-32/k_rem_pio2f.c (__kernel_rem_pio2f):
Likewise.
2016-08-18 Florian Weimer <fweimer@redhat.com>
[BZ #16907]

10
sysdeps/ieee754/dbl-64/k_rem_pio2.c
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@ -132,6 +132,7 @@ static char rcsid[] = "$NetBSD: k_rem_pio2.c,v 1.7 1995/05/10 20:46:25 jtc Exp $
#include <math.h>
#include <math_private.h>
#include <libc-internal.h>
static const int init_jk[] = {2,3,4,6}; /* initial value for jk */
@ -251,8 +252,17 @@ recompute:
j |= iq[i];
if (j == 0) /* need recomputation */
{
/* On s390x gcc 6.1 -O3 produces the warning "array subscript is below
array bounds [-Werror=array-bounds]". Only __ieee754_rem_pio2l
calls __kernel_rem_pio2 for normal numbers and |x| > pi/4 in case
of ldbl-96 and |x| > 3pi/4 in case of ldbl-128[ibm].
Thus x can't be zero and ipio2 is not zero, too. Thus not all iq[]
values can't be zero. */
DIAG_PUSH_NEEDS_COMMENT;
DIAG_IGNORE_NEEDS_COMMENT (6.1, "-Warray-bounds");
for (k = 1; iq[jk - k] == 0; k++)
; /* k = no. of terms needed */
DIAG_POP_NEEDS_COMMENT;
for (i = jz + 1; i <= jz + k; i++) /* add q[jz+1] to q[jz+k] */
{

10
sysdeps/ieee754/flt-32/k_rem_pio2f.c
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@ -19,6 +19,7 @@ static char rcsid[] = "$NetBSD: k_rem_pio2f.c,v 1.4 1995/05/10 20:46:28 jtc Exp
#include <math.h>
#include <math_private.h>
#include <libc-internal.h>
/* In the float version, the input parameter x contains 8 bit
integers, not 24 bit integers. 113 bit precision is not supported. */
@ -122,7 +123,16 @@ recompute:
j = 0;
for (i=jz-1;i>=jk;i--) j |= iq[i];
if(j==0) { /* need recomputation */
/* On s390x gcc 6.1 -O3 produces the warning "array subscript is
below array bounds [-Werror=array-bounds]". Only
__ieee754_rem_pio2f calls __kernel_rem_pio2f for normal
numbers and |x| ~> 2^7*(pi/2). Thus x can't be zero and
ipio2 is not zero, too. Thus not all iq[] values can't be
zero. */
DIAG_PUSH_NEEDS_COMMENT;
DIAG_IGNORE_NEEDS_COMMENT (6.1, "-Warray-bounds");
for(k=1;iq[jk-k]==0;k++); /* k = no. of terms needed */
DIAG_POP_NEEDS_COMMENT;
for(i=jz+1;i<=jz+k;i++) { /* add q[jz+1] to q[jz+k] */
f[jx+i] = (float) ipio2[jv+i];