[Bug ipa/95336] New: Bad code gen omnetpp_r aarch64

["erick.ochoa@theobroma-systems.com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95336

            Bug ID: 95336
           Summary: Bad code gen omnetpp_r aarch64
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ipa
          Assignee: unassigned at gcc dot gnu.org
          Reporter: erick.ochoa@theobroma-systems.com
                CC: marxin at gcc dot gnu.org
  Target Milestone: ---

Hello,

I have been using a configuration file to compile and run CPU2017. This
configuration file worked well with gcc9, but it doesn't seem to work well with
gcc10. I am aware of the instructions outlined in "Porting to GCC 10" [0] and I
believe I have followed them. However, at least for omnetpp_r there still
seemed to be an issue. Compilation succeeded, gave several warnings (including
the following):

simulator/matchexpression.tab.cc: In function
'matchexpressionyyparse.constprop.isra':
simulator/matchexpression.tab.cc:1444:37: warning: argument 1 value
'18446744073709551615' exceeds maximum object size 9223372036854775807
[-Walloc-size-larger-than=]
 1444 |      yymsg = (char *) YYSTACK_ALLOC (yyalloc);
      |          

and immediately segfaulted.

I used the following compiler flags:

-flto -fcommon -O3

I noticed that if I reduce the optimization level to -O2, there is no segfault.

I did a bisection from

commit f47f687a97260b1a1305cbf2d7ee3d74b2916a74
Author: Richard Biener <rguenther@suse.de>
Date:   Thu Apr 25 17:58:56 2019 +0000

to:

commit 4945b4c2c8628bdd61b348ea5bd1f9b72537a36e (HEAD)
Author: Martin Liska <mliska@suse.cz>
Date:   Tue May 26 09:01:41 2020 +0200

and I found that the following commit may have introduced the error:

commit ff6686d2e5f797d6c6a36ad14a7084bc1dc350e4
Author: Martin Jambor <mjambor@suse.cz>
Date:   Fri Sep 20 00:25:04 2019 +0200

I am not sure if this is a known issue or if I'm doing something wrong. 

This is the latest GCC version that I know reproduces the error:

[eochoa@osprey1 ~]$ $HOME/code/gcc-inst/bin/gcc -v
Using built-in specs.
COLLECT_GCC=/home/eochoa/code/gcc-inst/bin/gcc
COLLECT_LTO_WRAPPER=/home/eochoa/code/gcc-inst/libexec/gcc/aarch64-unknown-linux-gnu/11.0.0/lto-wrapper
Target: aarch64-unknown-linux-gnu
Configured with: /home/eochoa/code/gcc/configure --disable-bootstrap
--disable-libsanitizer --enable-__cxa_atexit --enable-shared
--disable-libsanitizer --enable-languages=c,c++,fortran --enable-lto
--enable-gold --enable-linker-build-id --with-cpu-emag
--prefix=/home/eochoa/code/gcc-inst/
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 11.0.0 20200526 (experimental) (GCC)

[0] https://gcc.gnu.org/gcc-10/porting_to.html