[Bug target/66174] New: [6 Regression] ICE: in extract_insn, at recog.c:2341 (unrecognizable insns) with -ftree-vectorize -mavx512ifma

["zsojka at seznam dot cz" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66174

            Bug ID: 66174
           Summary: [6 Regression] ICE: in extract_insn, at recog.c:2341
                    (unrecognizable insns) with -ftree-vectorize
                    -mavx512ifma
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zsojka at seznam dot cz
  Target Milestone: ---

Created attachment 35554
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35554&action=edit
reduced testcase

Compiler output:
$ gcc -O -ftree-vectorize -mavx512ifma testcase.c
testcase.c: In function 'foo':
testcase.c:27:1: error: unrecognizable insn:
 }
 ^
(insn 56 55 57 4 (set (reg:V16SI 155 [ D.2772 ])
        (vec_merge:V16SI (reg:V16SI 154 [ vect__9.11 ])
            (reg:V16SI 153 [ vect__9.10 ])
            (const_int 43690 [0xaaaa]))) testcase.c:16 -1
     (nil))
testcase.c:27:1: internal compiler error: in extract_insn, at recog.c:2341
0xae8418 _fatal_insn(char const*, rtx_def const*, char const*, int, char
const*)
        /mnt/svn/gcc-trunk/gcc/rtl-error.c:110
0xae84a8 _fatal_insn_not_found(rtx_def const*, char const*, int, char const*)
        /mnt/svn/gcc-trunk/gcc/rtl-error.c:118
0xa9e513 extract_insn(rtx_insn*)
        /mnt/svn/gcc-trunk/gcc/recog.c:2341
0x867b47 instantiate_virtual_regs_in_insn
        /mnt/svn/gcc-trunk/gcc/function.c:1598
0x867b47 instantiate_virtual_regs
        /mnt/svn/gcc-trunk/gcc/function.c:1966
0x867b47 execute
        /mnt/svn/gcc-trunk/gcc/function.c:2015
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.

Tested revisions:
r223190 - ICE
5 r222437 - OK