Patchwork Update changes.html about -Wno-aggressive-loop-optimizations

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Submitter Jakub Jelinek
Date March 22, 2013, 10:26 a.m.
Message ID <20130322102627.GX12913@tucnak.redhat.com>
Download mbox | patch
Permalink /patch/229960/
State New
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Comments

Jakub Jelinek - March 22, 2013, 10:26 a.m.
Hi!

This new warning switch hasn't been mentioned in changes.html, the following
patch fixes that.  Is this ok, or do you have better wording?


	Jakub
Richard Guenther - March 22, 2013, 10:33 a.m.
On Fri, 22 Mar 2013, Jakub Jelinek wrote:

> Hi!
> 
> This new warning switch hasn't been mentioned in changes.html, the following
> patch fixes that.  Is this ok, or do you have better wording?

No, looks ok to me.

Richard.

> --- htdocs/gcc-4.8/changes.html	14 Mar 2013 01:13:56 -0000	1.108
> +++ htdocs/gcc-4.8/changes.html	22 Mar 2013 10:22:37 -0000
> @@ -32,7 +32,12 @@ the number of iterations of loops using 
>  standards.  This may cause non-conforming programs to no longer work as
>  expected, such as SPEC CPU 2006 464.h264ref and 416.gamess.  A new
>  option, <code>-fno-aggressive-loop-optimizations</code>, was added
> -to disable this aggressive analysis.</p>
> +to disable this aggressive analysis.  In some loops that have known
> +constant number of iterations, but undefined behavior is known to occur
> +in the loop before reaching or during the last iteration, GCC will warn
> +about the undefined behavior in the loop instead of deriving lower upper
> +bound of the number of iterations for the loop.  The warning
> +can be disabled with <code>-Wno-aggressive-loop-optimizations</code>.</p>
>  
>  <p>On ARM, a bug has been fixed in GCC's implementation of the AAPCS
>  rules for the layout of vectors that could lead to wrong code being
> 
> 	Jakub
> 
>

Patch

--- htdocs/gcc-4.8/changes.html	14 Mar 2013 01:13:56 -0000	1.108
+++ htdocs/gcc-4.8/changes.html	22 Mar 2013 10:22:37 -0000
@@ -32,7 +32,12 @@  the number of iterations of loops using 
 standards.  This may cause non-conforming programs to no longer work as
 expected, such as SPEC CPU 2006 464.h264ref and 416.gamess.  A new
 option, <code>-fno-aggressive-loop-optimizations</code>, was added
-to disable this aggressive analysis.</p>
+to disable this aggressive analysis.  In some loops that have known
+constant number of iterations, but undefined behavior is known to occur
+in the loop before reaching or during the last iteration, GCC will warn
+about the undefined behavior in the loop instead of deriving lower upper
+bound of the number of iterations for the loop.  The warning
+can be disabled with <code>-Wno-aggressive-loop-optimizations</code>.</p>
 
 <p>On ARM, a bug has been fixed in GCC's implementation of the AAPCS
 rules for the layout of vectors that could lead to wrong code being