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* [Bug target/57057] New: Bad optimization on x86 for minps and maxps
@ 2013-04-24 16:41 mathias at gaunard dot com
2013-04-24 16:42 ` [Bug target/57057] " mathias at gaunard dot com
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: mathias at gaunard dot com @ 2013-04-24 16:41 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57057
Bug #: 57057
Summary: Bad optimization on x86 for minps and maxps
Classification: Unclassified
Product: gcc
Version: 4.7.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: mathias@gaunard.com
When optimization -O1 or greater is enabled, minps and maxps will incorrectly
deal with nan values.
icc gives the correct result.
See the attached C testcase, with -O0 it displays the correct result:
res1 = (1.000000 1.000000 1.000000 1.000000)
res2 = (-nan -nan -nan -nan)
res3 = (1.000000 1.000000 1.000000 1.000000)
res4 = (-nan -nan -nan -nan)
With -O1 it displays
res1 = (1.000000 1.000000 1.000000 1.000000)
res2 = (1.000000 1.000000 1.000000 1.000000)
res3 = (-nan -nan -nan -nan)
res4 = (-nan -nan -nan -nan)
The same also happens with the double-precision and AVX variants.
^ permalink raw reply [flat|nested] 4+ messages in thread* [Bug target/57057] Bad optimization on x86 for minps and maxps 2013-04-24 16:41 [Bug target/57057] New: Bad optimization on x86 for minps and maxps mathias at gaunard dot com @ 2013-04-24 16:42 ` mathias at gaunard dot com 2013-04-25 8:14 ` rguenth at gcc dot gnu.org 2021-07-29 23:43 ` pinskia at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: mathias at gaunard dot com @ 2013-04-24 16:42 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57057 --- Comment #1 from Mathias Gaunard <mathias at gaunard dot com> 2013-04-24 16:42:23 UTC --- Created attachment 29931 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=29931 bad optimisation testcase ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/57057] Bad optimization on x86 for minps and maxps 2013-04-24 16:41 [Bug target/57057] New: Bad optimization on x86 for minps and maxps mathias at gaunard dot com 2013-04-24 16:42 ` [Bug target/57057] " mathias at gaunard dot com @ 2013-04-25 8:14 ` rguenth at gcc dot gnu.org 2021-07-29 23:43 ` pinskia at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: rguenth at gcc dot gnu.org @ 2013-04-25 8:14 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57057 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |wrong-code Target| |x86_64-*-*, i?86-*-* Status|UNCONFIRMED |NEW Last reconfirmed| |2013-04-25 Ever Confirmed|0 |1 --- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> 2013-04-25 08:14:23 UTC --- That it's "fixed" with -O1 is because the different MINPS invocations are CSEd and only the first one is carried out. The issue here is that MINPS is not commutative, but the SMIN RTX code is specified as being commutative. Which means with !flag_finite_math_only the x86 backend has to use an UNSPEC to expand __builtin_ia32_minps and friends. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/57057] Bad optimization on x86 for minps and maxps 2013-04-24 16:41 [Bug target/57057] New: Bad optimization on x86 for minps and maxps mathias at gaunard dot com 2013-04-24 16:42 ` [Bug target/57057] " mathias at gaunard dot com 2013-04-25 8:14 ` rguenth at gcc dot gnu.org @ 2021-07-29 23:43 ` pinskia at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-07-29 23:43 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57057 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Resolution|--- |DUPLICATE Status|NEW |RESOLVED --- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> --- This was fixed for GCC 6.3+ and is a dup of bug 72867. *** This bug has been marked as a duplicate of bug 72867 *** ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-07-29 23:43 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2013-04-24 16:41 [Bug target/57057] New: Bad optimization on x86 for minps and maxps mathias at gaunard dot com 2013-04-24 16:42 ` [Bug target/57057] " mathias at gaunard dot com 2013-04-25 8:14 ` rguenth at gcc dot gnu.org 2021-07-29 23:43 ` pinskia at gcc dot gnu.org
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