[Bug tree-optimization/63569] [5.0 Regression] Wrong code with volatile and ICF

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63569

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Created attachment 33743
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33743&action=edit
A Testcase which ICEs instead of just wrong code

Compile with -O2.
The ICE you get:
t3.c: In function ‘register_netdevice’:
t3.c:66:1: internal compiler error: in verify_ssa, at tree-ssa.c:936
 }
 ^
0xbebecf verify_ssa(bool, bool)
    /home/pinskia/src/toolchain/scripts/../src/gcc/tree-ssa.c:936
0x95292d execute_function_todo
    /home/pinskia/src/toolchain/scripts/../src/gcc/passes.c:1762
0x95310d do_per_function
    /home/pinskia/src/toolchain/scripts/../src/gcc/passes.c:1489
0x95310d do_per_function
    /home/pinskia/src/toolchain/scripts/../src/gcc/passes.c:1479
0x95321b execute_todo
    /home/pinskia/src/toolchain/scripts/../src/gcc/passes.c:1812
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.