[Bug tree-optimization/103317] New: Spec 2017 benchmark blender_r fails with -Ofast on PowerPc (power9, power10)

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103317

            Bug ID: 103317
           Summary: Spec 2017 benchmark blender_r fails with -Ofast on
                    PowerPc (power9, power10)
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: meissner at gcc dot gnu.org
  Target Milestone: ---

Created attachment 51832
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51832&action=edit
Preprocessed .i file that shows the bug (gzipped).

As of November 17th, the current trunk compiler for GCC 12 fails when compiling
the Spec 2017 benchmark blender_r for PowerPC using -Ofast.  I see failures for
both power9 and power10 systems.  Here is the traceback:

libpng/png.c: In function 'png_build_gamma_table':
libpng/png.c:2872:1: error: definition in block 19 does not dominate use in
block 18
 2872 | }
      | ^
for SSA_NAME: _57 in statement:
shift_48 = PHI <_57(18), _58(19)>
PHI argument
_57
for PHI node
shift_48 = PHI <_57(18), _58(19)>
during GIMPLE pass: phiopt
libpng/png.c:2872:1: internal compiler error: verify_ssa failed
0x10c5f64b verify_ssa(bool, bool)
        /home/meissner/fsf-src/trunk-2021-11-17/gcc/tree-ssa.c:1211
0x1080e97f execute_function_todo
        /home/meissner/fsf-src/trunk-2021-11-17/gcc/passes.c:2049
0x1080f613 execute_todo
        /home/meissner/fsf-src/trunk-2021-11-17/gcc/passes.c:2096
Please submit a full bug report,
with preprocessed source if appropriate.

I see it with -O2, -O3, and -Ofast, using -mcpu=power8, -mcpu=power9, and
-mcpu=power10 on PowerPC little endian systems. It did compile with the
compiler I checked out on November 4th.

I will attach the .i file compressed with gzip.