[Bug tree-optimization/55838] New: ICE in extract_insn (unrecognizable insn) with -O -funroll-loops

["antoine.balestrat at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55838

             Bug #: 55838
           Summary: ICE in extract_insn (unrecognizable insn) with -O
                    -funroll-loops
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: antoine.balestrat@gmail.com


Hi ! This very simple testcase makes GCC 4.8.0 as of 20121231 (and 4.7.2 as
well) crash with -O -funroll-loops.
I hope this is not a dup.


$ cat insn.c
int a;
unsigned char c;

void f(void)
{
    while(c++ < 2)
        c = a += 129;
}

$ xgcc -O -funroll-loops -w insn.c
insn.c: In function âfâ:
insn.c:8:1: error: unrecognizable insn:
 }
 ^
(insn 93 92 94 3 (set (reg:QI 127)
        (const_int 129 [0x81])) -1
     (nil))
insn.c:8:1: internal compiler error: in extract_insn, at recog.c:2152
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.


I wish you a happy new year !