[Bug tree-optimization/23449] New: vortex fails without -fno-strict-aliasing

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

The SPEC CPU2000 test vortex segfaults on powerpc64-linux with current
mainline for either -m32 or -m64 with -O2.  It succeeds when compiled
with -fno-strict-aliasing.  It's quite likely that this is due to
invalid code in vortex itself, but nothing jumped out at me.  I'm
about to go on a two-week vacation, so I'm recording this in case
someone else would like to continue the investigation.
                                                                                
If mem00.c is compiled with "-O2 -fno-strict-aliasing" and the rest
of vortex is compiled with "-O2", the test passes.
                                                                                
Variables ChunkAddrChunk and NumChunkChunks, defined in mem00.h, are
static and their values never change.  If either one is made global
instead, the test passes.  If either variable is replaced with a
global variable with the same value at lines 240-248, the test passes.
If the for loop at line 240 is changed to increment ChunkChunk as the
third expression in for loop instead of in the second expression, the
test passes.

-- 
           Summary: vortex fails without -fno-strict-aliasing
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: janis at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org
GCC target triplet: powerpc-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23449