[Bug tree-optimization/25211] New: verify_ssa ICE for mesa with -Os -ftree-loop-linear

["janis at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

Current trunk and 4.1 branch ICE on powerpc-linux compiling mesa
from SPEC CPU2000:

elm3b11% /opt/gcc-nightly/4.1/bin/gcc -c -Os -ftree-loop-linear mesa1201.c
mesa1201.c: In function ?foo?:
mesa1201.c:7: error: definition in block 9 does not dominate use in block 3
for SSA_NAME: q_25 in statement:
q_1 = PHI <q_15(0), q_25(3)>;
PHI argument
q_25
for PHI node
q_1 = PHI <q_15(0), q_25(3)>;
mesa1201.c:7: internal compiler error: verify_ssa failed

The testcase passes with GCC 4.0.2 and with the 4.0 branch.
A regression hunt identified the following very large patch:

  http://gcc.gnu.org/viewcvs?view=rev&rev=102356
  r102356 | irar | 2005-07-25 12:05:07 +0000 (Mon, 25 Jul 2005)

I'll attach a minimized testcase.


-- 
           Summary: verify_ssa ICE for mesa with -Os -ftree-loop-linear
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: janis at gcc dot gnu dot org
GCC target triplet: powerpc-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25211