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From: "vincent at vinc17 dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/46080] [4.4/4.5/4.6 Regression] incorrect precision of sqrtf builtin for x87 arithmetic (-mfpmath=387)
Date: Wed, 20 Oct 2010 01:52:00 -0000 [thread overview]
Message-ID: <20101020015200.HRiXTOr4YXJOIR0IzrsZE1YDKry56_va0kLw6i8LN6w@z> (raw)
In-Reply-To: <bug-46080-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46080
--- Comment #2 from Vincent Lefèvre <vincent at vinc17 dot org> 2010-10-20 01:51:56 UTC ---
Created attachment 22089
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22089
sh script to test sqrtf
Similar problems can also be found with:
printf ("%.60f\n%.60f\n%.60f\n", sqrtf(x), sqrtf(x), sqrtf(x));
I've found that every GCC version I could test was showing some incorrect
behavior (but GCC 4.2.4 was the most consistent one). With the attached script,
I get:
-DSEP -O0 -O1 -O2
GCC 3.4.6 SSS SSS SDD SDD
GCC 4.1.3 SSS SSS DSS DDS
GCC 4.2.4 SSS SSS DDD DDD (x86)
GCC 4.3.5 SSS SSS DSS DDD (ditto with GCC 4.3.2 on x86)
GCC 4.4.5 DSS SSD DSS DDD
where S means that one gets the result in single precision (as expected) and D
means that one gets the result in double precision.
next prev parent reply other threads:[~2010-10-20 1:52 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-19 8:55 [Bug target/46080] New: " vincent at vinc17 dot org
2010-10-19 10:49 ` [Bug target/46080] [4.4/4.5/4.6 Regression] " rguenth at gcc dot gnu.org
2010-10-20 1:52 ` vincent at vinc17 dot org [this message]
2010-10-20 8:29 ` ubizjak at gmail dot com
2010-10-20 9:39 ` jakub at gcc dot gnu.org
2010-10-20 9:54 ` zimmerma+gcc at loria dot fr
2010-10-20 10:46 ` jakub at gcc dot gnu.org
2010-10-20 23:43 ` vincent at vinc17 dot org
2010-10-20 23:49 ` pinskia at gcc dot gnu.org
2010-10-21 19:26 ` zimmerma+gcc at loria dot fr
2010-10-21 20:56 ` jakub at gcc dot gnu.org
2010-10-22 6:56 ` zimmerma+gcc at loria dot fr
2010-10-26 13:41 ` jakub at gcc dot gnu.org
2010-11-12 14:35 ` rguenth at gcc dot gnu.org
2010-11-16 10:56 ` jakub at gcc dot gnu.org
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