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[Bug target/57057] New: Bad optimization on x86 for minps and maxps
- From: "mathias at gaunard dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Wed, 24 Apr 2013 16:41:55 +0000
- Subject: [Bug target/57057] New: Bad optimization on x86 for minps and maxps
- Auto-submitted: auto-generated
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.