Remove noce_mem_write_may_trap_or_fault_p in ifcvt

[Richard Biener]

On Wed, Nov 25, 2015 at 2:18 PM, Michael Matz <matz@suse.de> wrote:
> Hi,
>
> On Wed, 25 Nov 2015, Richard Biener wrote:
>
>> I don't think so.  Btw, if you want to add this please add a new gimple
>> predicate to identify "memory barrier" (any call or asm with a VDEF).
>
>       if (is_gimple_call (stmt) && !nonfreeing_call_p (stmt))
>         nt_call_phase++;

That looks bogus to me.  It misses asm()s and at least today
nonfreeing_call_p too much checks what it sounds like it checks.
In practice it might work though.  At least all the __sync_* and
__atomic_* calls are _not_ barriers this way.  A pthread_mutex_lock is
though as we don't have a builtin for it.

I'd change the above to a conservative

   if ((is_gimple_call (stmt) || is_gimple_asm (stmt)) && gimple_vuse (stmt))

Richard.

>
> Ciao,
> Michael.