[Bug tree-optimization/46049] New: [4.6 Regression] ICE: in expand_widen_pattern_expr, at optabs.c:522 with -ftree-vectorize

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46049

           Summary: [4.6 Regression] ICE: in expand_widen_pattern_expr, at
                    optabs.c:522 with -ftree-vectorize
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: zsojka@seznam.cz


Created attachment 22062
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22062
reduced testcase

The testcase crashes with two different ICEs, depending on supplied flags.

ICE 1:
$ gcc -O -ftree-vectorize pr46049.c  
pr46049.c: In function 'foo':
pr46049.c:9:6: internal compiler error: in expand_widen_pattern_expr, at
optabs.c:522
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

ICE 2:
$ gcc -O -ftree-vectorize -ftree-pre pr46049.c 
pr46049.c: In function 'foo':
pr46049.c:18:1: error: unrecognizable insn:
(insn 62 61 63 6 (set (reg:V4SI 158)
        (vec_merge:V4SI (vec_duplicate:V4SI (reg/v:HI 152 [ x ]))
            (const_vector:V4SI [
                    (const_int 0 [0])
                    (const_int 0 [0])
                    (const_int 0 [0])
                    (const_int 0 [0])
                ])
            (const_int 1 [0x1]))) pr46049.c:11 -1
     (nil))
pr46049.c:18:1: internal compiler error: in extract_insn, at recog.c:2110
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

Tested versions:
r165540 - crash (with PR45352 fix, but that affects only haifa scheduler)
r163636 - OK