[Bug rtl-optimization/47698] CMOV accessing volatile memory with read side effect

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47698

--- Comment #5 from H.J. Lu <hjl.tools at gmail dot com> 2011-02-11 17:48:43 UTC ---
(In reply to comment #4)
> noce_operand_ok doesn't disregard volatile MEMs:
> 
>   /* We special-case memories, so handle any of them with
>      no address side effects.  */
>   if (MEM_P (op))
>     return ! side_effects_p (XEXP (op, 0));
> 
> But I don't see where we would handle volatile MEMs in any sensible
> way.  We happily fiddle with such operands resulting in the problem.

cmov pattern should disallow operand with volatile MEM.