[PATCH] Fix -Wunused-var-35.C (was Re: [PATCH][C++] Improve compile-time by ordering expensive checks last)

Richard Biener rguenther@suse.de
Thu Apr 25 12:16:00 GMT 2019


On Thu, 25 Apr 2019, Jakub Jelinek wrote:

> On Thu, Apr 25, 2019 at 01:39:02PM +0200, Richard Biener wrote:
> > > Regtested on x86_64-linux and i686-linux, ok for trunk?
> > 
> > The patch would be obvious but I wonder how the above can change 
> > anything...  (but I can reproduce with even only that change)
> 
> Haven't stepped through it in a debugger, but I bet it is the
> fold_non_dependent_expr call in null_ptr_cst_p which is done for C++98 only.
> That will mark it as TREE_USED in the end most likely and the
> earlier fix for the PR44648 issues, r249083, was also about not trying to
> fold the stuff early.

Ah, OK, that makes "sense" (well, it doesn't really make sense for
a function called null_ptr_cst_p to behave this way...)

Richard.

> > > 2019-04-25  Jakub Jelinek  <jakub@redhat.com>
> > > 
> > > 	PR c++/44648
> > > 	* g++.dg/warn/Wunused-var-35.C: Remove xfail.
> > > 
> > > --- gcc/testsuite/g++.dg/warn/Wunused-var-35.C.jj	2019-02-04 09:44:31.365413407 +0100
> > > +++ gcc/testsuite/g++.dg/warn/Wunused-var-35.C	2019-04-25 13:24:49.717065815 +0200
> > > @@ -11,9 +11,8 @@ int main()
> > >    else
> > >      return 1;
> > >  
> > > -  if (const bool b2 = 1) // { dg-warning "\\\[-Wunused-variable\\\]" "bug" { xfail c++98_only } }
> > > +  if (const bool b2 = 1) // { dg-warning "\\\[-Wunused-variable\\\]" }
> > >      return 0;
> > >    else
> > >      return 1;
> > >  }
> > > -
> 
> 	Jakub
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE Linux GmbH, Maxfeldstrasse 5, 90409 Nuernberg, Germany;
GF: Felix Imendörffer, Mary Higgins, Sri Rasiah; HRB 21284 (AG NÌrnberg)


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