[Bug target/57057] New: Bad optimization on x86 for minps and maxps

[mathias at gaunard dot com]

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.