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* Re: c/10339: [sparc] Invalid optimization: replacing strncmp by memcmp
@ 2003-04-07 18:42 bangerth
0 siblings, 0 replies; 3+ messages in thread
From: bangerth @ 2003-04-07 18:42 UTC (permalink / raw)
To: gcc-bugs, gcc-prs, nobody, ubell
Old Synopsis: strncmp generates imPure code
New Synopsis: [sparc] Invalid optimization: replacing strncmp by memcmp
State-Changed-From-To: feedback->analyzed
State-Changed-By: bangerth
State-Changed-When: Mon Apr 7 18:42:46 2003
State-Changed-Why:
Confirmed. See audit trail for more information
http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=10339
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: c/10339: [sparc] Invalid optimization: replacing strncmp by memcmp
@ 2003-04-09 5:56 Richard Henderson
0 siblings, 0 replies; 3+ messages in thread
From: Richard Henderson @ 2003-04-09 5:56 UTC (permalink / raw)
To: nobody; +Cc: gcc-prs
The following reply was made to PR optimization/10339; it has been noted by GNATS.
From: Richard Henderson <rth@redhat.com>
To: bangerth@dealii.org, gcc-bugs@gcc.gnu.org, ubell@sleepycat.com,
gcc-gnats@gcc.gnu.org
Cc:
Subject: Re: c/10339: [sparc] Invalid optimization: replacing strncmp by memcmp
Date: Tue, 8 Apr 2003 22:47:08 -0700
On Tue, Apr 08, 2003 at 10:43:36AM +0930, Alan Modra wrote:
> A more reasonable objection to the
> strncmp -> memcmp transformation is that a memcmp implementation
> might load multiple words into registers (say a cache-line worth),
> before comparing.
Agreed.
r~
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: c/10339: [sparc] Invalid optimization: replacing strncmp by memcmp
@ 2003-04-08 1:16 Alan Modra
0 siblings, 0 replies; 3+ messages in thread
From: Alan Modra @ 2003-04-08 1:16 UTC (permalink / raw)
To: nobody; +Cc: gcc-prs
The following reply was made to PR optimization/10339; it has been noted by GNATS.
From: Alan Modra <amodra@bigpond.net.au>
To: bangerth@dealii.org, gcc-bugs@gcc.gnu.org, ubell@sleepycat.com,
gcc-gnats@gcc.gnu.org
Cc:
Subject: Re: c/10339: [sparc] Invalid optimization: replacing strncmp by memcmp
Date: Tue, 08 Apr 2003 10:43:36 +0930
On Mon, Apr 07, 2003 at 06:42:47PM -0000, bangerth@dealii.org wrote:
> Old Synopsis: strncmp generates imPure code
> New Synopsis: [sparc] Invalid optimization: replacing strncmp by memcmp
Also happens on powerpc-linux and powerpc64-linux. Incidentally,
I think Andreas' suggestion that memcmp is allowed to compare from
the upper end of the arrays is not very likely to happen given
memcmp's return value. A more reasonable objection to the
strncmp -> memcmp transformation is that a memcmp implementation
might load multiple words into registers (say a cache-line worth),
before comparing.
--
Alan Modra
IBM OzLabs - Linux Technology Centre
^ permalink raw reply [flat|nested] 3+ messages in thread
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2003-04-07 18:42 c/10339: [sparc] Invalid optimization: replacing strncmp by memcmp bangerth
2003-04-08 1:16 Alan Modra
2003-04-09 5:56 Richard Henderson
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