Get rid of array-bounds warning in __kernel_rem_pio2[f] with gcc 6.1 -O3.
Commit Message
On 08/10/2016 01:38 PM, Joseph Myers wrote:
> On Tue, 2 Aug 2016, Stefan Liebler wrote:
>
>> diff --git a/sysdeps/ieee754/dbl-64/k_rem_pio2.c b/sysdeps/ieee754/dbl-64/k_rem_pio2.c
>
>> + /* 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_pio2f() for normal numbers and |x| > 3pi/4.
>
> __kernel_rem_pio2f seems like the wrong function to reference in a comment
> in this file. Please review the actual call sequences in each case to
> make sure the right functions are referenced. Also, the GNU Coding
> Standards say not to use () after a function name when referencing the
> function:
>
> Please do not write @samp{()} after a function name just to indicate
> it is a function. @code{foo ()} is not a function, it is a function
> call with no arguments.
>
>> + /* 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
>
> Likewise, don't use () after the function name.
>
I've reviewed the call sequences and adjusted the comment and removed
the () after the function names.
Here is the updated patch.
Okay to commit?
Bye
Stefan
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.
Comments
On Wed, 17 Aug 2016, Stefan Liebler wrote:
> I've reviewed the call sequences and adjusted the comment and removed the ()
> after the function names.
> Here is the updated patch.
>
> Okay to commit?
OK.
On 08/17/2016 05:32 PM, Joseph Myers wrote:
> On Wed, 17 Aug 2016, Stefan Liebler wrote:
>
>> I've reviewed the call sequences and adjusted the comment and removed the ()
>> after the function names.
>> Here is the updated patch.
>>
>> Okay to commit?
>
> OK.
>
Commited.
@@ -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] */
{
@@ -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];