Re: [PATCH] Fix PR ipa/64813

[Martin LiÅka <mliska at suse dot cz>]

On 02/10/2015 05:00 PM, Jakub Jelinek wrote:
> On Tue, Feb 10, 2015 at 04:56:40PM +0100, Martin LiÅka wrote:
> > On 02/10/2015 01:50 PM, Richard Biener wrote:
> > > On Tue, Feb 10, 2015 at 12:07 PM, Martin LiÅka <mliska@suse.cz> wrote:
> > > > Hello.
> > > >
> > > > Following patch is fix for PR ipa/64813. The patch was tested on a darwin
> > > > target
> > > > by Dominique.
> > > >
> > > > Ready for trunk?
> > >
> > > -      if (!(gimple_call_flags (call) & ECF_NORETURN))
> > > +      if (!alias_is_noreturn)
> > >
> > > that was technically unnecessary, right?  The call flags properly
> > > return ECF_NORETURN already?
> > >
> > > Ok if that is the case.
> >
> > Hi.
> >
> > You are right, !(gimple_call_flags (call) & ECF_NORETURN) returns a correct value.
> > Motivation for replacement is not to repeat the same condition, I hope the value
> > of alias_is_noreturn is correct in all uses.
>
> And gimple_call_flags (call) & ECF_NORETURN doesn't?  I mean, if you could
> initialize alias_is_noreturn to that, it would be nicer.
>
> 	Jakub

Hello.

There are actually 3 places I need to guard if a function non-return.
First place is responsible for result type creation:

      /* Build call to the function being thunked.  */
      if (!VOID_TYPE_P (restype) && !alias_is_noreturn)

Where I can create guard just based on TREE_THIS_VOLATILE of the called function.
Once the new gimple call is created I can use:

(gimple_call_flags (call) & ECF_NORETURN

So that's the reason I create one bool value (alias_is_noreturn) and the very
beginning of expand_thunk method. Dost it make sense?

Thanks,
Martin