diff mbox

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

Message ID nnpm3f$iik$1@blaine.gmane.org
State Superseded
Headers show

Commit Message

Stefan Liebler Aug. 2, 2016, 8:37 a.m. UTC
On 08/01/2016 04:12 PM, Mike Frysinger wrote:
> On 25 Jul 2016 17:55, Stefan Liebler wrote:
>> +	  /* 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. Thus
>> +	     x can't be zero and ipio2 is not zero, too. Thus not all iq[]
>> +	     values can't be zero.  */
>
> GNU style puts two spaces after the period
> -mike
>
Oops. I missed that.
Here is an update.
Thanks.
Stefan

Comments

Stefan Liebler Aug. 10, 2016, 10:08 a.m. UTC | #1
PING

On 08/02/2016 10:37 AM, Stefan Liebler wrote:
> On 08/01/2016 04:12 PM, Mike Frysinger wrote:
>> On 25 Jul 2016 17:55, Stefan Liebler wrote:
>>> +      /* 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. Thus
>>> +         x can't be zero and ipio2 is not zero, too. Thus not all iq[]
>>> +         values can't be zero.  */
>>
>> GNU style puts two spaces after the period
>> -mike
>>
> Oops. I missed that.
> Here is an update.
> Thanks.
> Stefan
Joseph Myers Aug. 10, 2016, 11:38 a.m. UTC | #2
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.
diff mbox

Patch

diff --git a/sysdeps/ieee754/dbl-64/k_rem_pio2.c b/sysdeps/ieee754/dbl-64/k_rem_pio2.c
index e58c9e8..db0a657 100644
--- a/sysdeps/ieee754/dbl-64/k_rem_pio2.c
+++ b/sysdeps/ieee754/dbl-64/k_rem_pio2.c
@@ -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 +252,16 @@  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_pio2f() for normal numbers and |x| > 3pi/4.
+	     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] */
 	    {
diff --git a/sysdeps/ieee754/flt-32/k_rem_pio2f.c b/sysdeps/ieee754/flt-32/k_rem_pio2f.c
index 392afdb..cca20aa 100644
--- a/sysdeps/ieee754/flt-32/k_rem_pio2f.c
+++ b/sysdeps/ieee754/flt-32/k_rem_pio2f.c
@@ -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];