This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH 1/4] Mark all member functions with memory models always inline


On Wed, Mar 20, 2013 at 11:46 AM, Jakub Jelinek <jakub@redhat.com> wrote:
> On Wed, Mar 20, 2013 at 11:38:03AM +0100, Richard Biener wrote:
>> Not without using information created by TER which is disabled for this
>> case because of different line information.  If TER would not be disabled
>> for this reason it would already work automagically.
>
> Would relaxing that in TER for constants help in the case of:
> static inline __attribute__((always_inline)) ...
> foo (..., int m = __ATOMIC_SEQ_CST)
> {
>   if (something)
>     bar ();
>   else
>     baz ();
>   __atomic_test_and_set (&x, m);
> }
>
> void
> test ()
> {
>   foo (..., __ATOMIC_HLE_ACQUIRE | __ATOMIC_SEQ_CST);
> }
> though?  I'd think as the temp = 0x10005; would be in a different bb, TER
> wouldn't do anything here, for -O1 of course CCP or similar would propagate
> that, but for -O0 we'd still have to walk the chain of SSA_NAMEs.

True.  I was for a long time thinking of running a CCP pass at -O0 ...
and only restrict what we sustitute into (builtin arguments and asm operands).

Walking the SSA def chain would also be possible - preferably from
cfgexpand.c when we process the stmt.  But you'll eventually lose
debug info like for

  int i = 1;
  __builtin_foo (i);

when we then never expand the SSA name def i_2 = 1 because we are
never visiting its use ...

Richard.

>         Jakub


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]