https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66186
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2015-05-18
CC| |jakub at gcc dot gnu.org
Summary|wrong code at -O3 on |[4.9/5/6 Regression] wrong
|x86_64-linux-gnu |code at -O3 on
| |x86_64-linux-gnu
Ever confirmed|0 |1
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with r204458. But most likely this is yet another case of the RTL bug
where stack pointer based accesses are considered as non-trapping, despite
being clearly out of bounds.
The pcom change only changed
f_I_lsm0.4_7 = f[65535];
which the compiler can see as being out of bounds access quickly (note, f is
int f[2]), but after the pcom change it uses
f_I_lsm0.4_7 = MEM[(int *)&f + 262140B];
and for some reason we don't consider that as clearly out of bounds access.
