[Bug target/68633] New: [i386, AVX-512] Spec2006/434. miscompares when executed on KNL

[kyukhin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68633

            Bug ID: 68633
           Summary: [i386, AVX-512] Spec2006/434. miscompares when
                    executed on KNL
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: kyukhin at gcc dot gnu.org
  Target Milestone: ---

Created attachment 36880
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36880&action=edit
Reproducer

Attached test case is reduced version of the problem.

To reproduce:
$ ./build-x86_64-linux/gcc/xgcc -B./build-x86_64-linux/gcc ~/test.c -O3
-march=knl
$ ~/sde/sde-internal-rs-7.31.0-2015-09-25-lin/sde64  -- ./a.out
libc: Fatal signal 6 (SIGABRT), code -6 in tid 34536^@
Aborted (core dumped)

This is most likely recent introduction of scalar masking. I suspect that order
of operands is
incorrect in the pattern