[Bug lto/42696] New: lto1 error with -fsigned-char and char comparison

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

SPEC CPU2006 tests 464.h264ref and 482.sphinx3 fail to build on powerpc64-linux
with "-m64 -lto -fsigned-char".  For some reason we've added the option
-fsigned-char to the SPEC config files for those two tests; without it both
tests fail at runtime for -m64, but it doesn't affect the results for -m32. 
The failure to build with -flto might be due to some problem with -fsigned-char
on powerpc64, rather than a problem with LTO.

Here's a minimized testcase:

---------------------
extern char *a;
extern int f;

void
foo (void)
{
  f = (*a != '-');
} 
---------------------

And here's what happens:

elm3b149% /home/janis/tools/gcc-trunk-anonsvn/bin/gcc -m64 -flto -fsigned-char
bug.c -c
elm3b149% /home/janis/tools/gcc-trunk-anonsvn/bin/gcc -m64 -flto -fsigned-char
bug.o -shared -o x.so
In function ?foo?:
lto1: error: type mismatch in indirect reference
<unnamed-signed:8>
<unnamed-unsigned:8>

D.1228_2 = *a.0_1;

lto1: internal compiler error: verify_stmts failed
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.
lto-wrapper: /home/janis/tools/gcc-trunk-anonsvn/bin/gcc returned 1 exit status
collect2: lto-wrapper returned 1 exit status

If the type of 'a' is signed char then everything works fine.


-- 
           Summary: lto1 error with -fsigned-char and char comparison
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: lto
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: janis at gcc dot gnu dot org
GCC target triplet: powerpc64-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42696