https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90020
Martin Liška <marxin at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |wrong-code
CC| |rguenth at gcc dot gnu.org
Summary|[8 regression] -O2 -Os |[7/8/9 regression] -O2 -Os
|x86-64 wrong code generated |x86-64 wrong code generated
|for GNU Emacs |for GNU Emacs
Known to fail| |7.4.0, 8.3.0, 9.0
--- Comment #3 from Martin Liška <marxin at gcc dot gnu.org> ---
I can confirm that even though the code is not so nice :)
I have 2 versions of the reduced test-case:
1)
$ gcc emacs0.c -Os -fno-strict-aliasing -g && valgrind ./a.out
==20746== Memcheck, a memory error detector
==20746== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==20746== Using Valgrind-3.14.0 and LibVEX; rerun with -h for copyright info
==20746== Command: ./a.out
==20746==
==20746== Invalid read of size 8
==20746== at 0x4011CF: select_window (emacs0.c:116)
==20746== by 0x40105A: main (emacs0.c:126)
==20746== Address 0xa is not stack'd, malloc'd or (recently) free'd
fails for 4.8.0+ except 4.9.x releases.
2)
$ gcc emacs.c -Os -fno-strict-aliasing && ./a.out
started failing with r238242
The problematic transformation:
<bb 2> [local count: 1073741824]:
_1 = PSEUDOVECTORP (window_6(D));
pretmp_9 = MEM[(struct window *)window_6(D)].contents;
if (_1 != 0)
goto <bb 3>; [50.00%]
else
goto <bb 4>; [50.00%]
happens in PRE. Richi can you please take a look?
