[Bug rtl-optimization/112415] New: [14 regression] Python 3.11 miscompiled with new RTL fold mem offset pass, since r14-4664-g04c9cf5c786b94

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112415

            Bug ID: 112415
           Summary: [14 regression] Python 3.11 miscompiled with new RTL
                    fold mem offset pass, since r14-4664-g04c9cf5c786b94
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: sjames at gcc dot gnu.org
                CC: danglin at gcc dot gnu.org, manolis.tsamis at vrull dot eu
  Target Milestone: ---

I've bisected this twice and come to r14-4664-g04c9cf5c786b94 ('Implement new
RTL optimizations pass: fold-mem-offsets'). -fno-fold-mem-offsets makes things
work.

Python 3.11.6 fails to build on HPPA since that commit with the built-Python
segfaulting during the build.

```
hppa2.0-unknown-linux-gnu-gcc -c -Wsign-compare -DNDEBUG     -O2 -pipe
-march=2.0 -fdiagnostics-color=always -frecord-gcc-switches -ggdb3 -fwrapv
-std=c11 -Wextra -Wno-unused-parameter -Wno-missing-field-init
ializers -Wstrict-prototypes -Werror=implicit-function-declaration
-fvisibility=hidden  -I./Include/internal  -I. -I./Include
-I/usr/include/ncursesw  -fPIC -DPy_BUILD_CORE -o Python/frozen.o
Python/frozen.c
./_bootstrap_python ./Tools/scripts/deepfreeze.py \
Python/frozen_modules/importlib._bootstrap.h:importlib._bootstrap \
Python/frozen_modules/importlib._bootstrap_external.h:importlib._bootstrap_external
\
Python/frozen_modules/zipimport.h:zipimport \
Python/frozen_modules/abc.h:abc \
Python/frozen_modules/codecs.h:codecs \
Python/frozen_modules/io.h:io \
Python/frozen_modules/_collections_abc.h:_collections_abc \
Python/frozen_modules/_sitebuiltins.h:_sitebuiltins \
Python/frozen_modules/genericpath.h:genericpath \
Python/frozen_modules/ntpath.h:ntpath \
Python/frozen_modules/posixpath.h:posixpath \
Python/frozen_modules/os.h:os \
Python/frozen_modules/site.h:site \
Python/frozen_modules/stat.h:stat \
Python/frozen_modules/importlib.util.h:importlib.util \
Python/frozen_modules/importlib.machinery.h:importlib.machinery \
Python/frozen_modules/runpy.h:runpy \
Python/frozen_modules/__hello__.h:__hello__ \
Python/frozen_modules/__phello__.h:__phello__ \
Python/frozen_modules/__phello__.ham.h:__phello__.ham \
Python/frozen_modules/__phello__.ham.eggs.h:__phello__.ham.eggs \
Python/frozen_modules/__phello__.spam.h:__phello__.spam \
Python/frozen_modules/frozen_only.h:frozen_only \
-o Python/deepfreeze/deepfreeze.c
make: *** [Makefile:1298: Python/deepfreeze/deepfreeze.c] Segmentation fault
(core dumped)
make: *** Waiting for unfinished jobs....
hppa2.0-unknown-linux-gnu-gcc -c -I./Modules/_decimal/libmpdec -DCONFIG_32=1
-DANSI=1 -Wsign-compare -DNDEBUG     -O2 -pipe -march=2.0
-fdiagnostics-color=always -frecord-gcc-switches -ggdb3 -fwrapv -std=c11
-Wextra -Wno-unused-parameter -Wno-missing-field-initializers
-Wstrict-prototypes -Werror=implicit-function-declaration -fvisibility=hidden 
-I./Include/internal  -I. -I./Include -I/usr/include/ncursesw  -fPIC -fPIC -o
Modules/_decimal/libmpdec/mpdecimal.o ./Modules/_decimal/libmpdec/mpdecimal.c
 * ERROR: dev-lang/python-3.11.6::gentoo failed (compile phase):
 *   emake failed
```