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Re: [PATCH][PR65802] Mark ifn_va_arg with ECF_NOTHROW
- From: Richard Biener <rguenther at suse dot de>
- To: Jan Hubicka <hubicka at ucw dot cz>
- Cc: Tom de Vries <Tom_deVries at mentor dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Tue, 21 Apr 2015 09:50:33 +0200 (CEST)
- Subject: Re: [PATCH][PR65802] Mark ifn_va_arg with ECF_NOTHROW
- Authentication-results: sourceware.org; auth=none
- References: <5535F7EF dot 1000305 at mentor dot com> <20150421074853 dot GA9659 at atrey dot karlin dot mff dot cuni dot cz>
On Tue, 21 Apr 2015, Jan Hubicka wrote:
> > Mark ifn_va_arg with ECF_NOTHROW
>
> You can defnitly make it ECF_LEAF too. I wonder if we can make it ECF_CONST or at leat PURE
> this would help to keep variadic functions const/pure that may be moderately interesting
> in practice.
Yes to ECF_LEAF but it isn't const or pure as it modifies the valist
argument so you can't for example DCE va_arg (...) if the result isn't
needed.
Richard.
> Honza
> >
> > 2015-04-20 Tom de Vries <tom@codesourcery.com>
> >
> > PR tree-optimization/65802
> > * internal-fn.def (VA_ARG): Add ECF_NOTROW to flags.
> >
> > * g++.dg/pr65802.C: New test.
> > ---
> > gcc/internal-fn.def | 2 +-
> > gcc/testsuite/g++.dg/pr65802.C | 29 +++++++++++++++++++++++++++++
> > 2 files changed, 30 insertions(+), 1 deletion(-)
> > create mode 100644 gcc/testsuite/g++.dg/pr65802.C
> >
> > diff --git a/gcc/internal-fn.def b/gcc/internal-fn.def
> > index f557c64..7e19313 100644
> > --- a/gcc/internal-fn.def
> > +++ b/gcc/internal-fn.def
> > @@ -62,4 +62,4 @@ DEF_INTERNAL_FN (ADD_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
> > DEF_INTERNAL_FN (SUB_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
> > DEF_INTERNAL_FN (MUL_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
> > DEF_INTERNAL_FN (TSAN_FUNC_EXIT, ECF_NOVOPS | ECF_LEAF | ECF_NOTHROW, NULL)
> > -DEF_INTERNAL_FN (VA_ARG, 0, NULL)
> > +DEF_INTERNAL_FN (VA_ARG, ECF_NOTHROW, NULL)
> > diff --git a/gcc/testsuite/g++.dg/pr65802.C b/gcc/testsuite/g++.dg/pr65802.C
> > new file mode 100644
> > index 0000000..26e5317
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/pr65802.C
> > @@ -0,0 +1,29 @@
> > +// { dg-do compile }
> > +// { dg-options "-O0" }
> > +
> > +typedef int tf ();
> > +
> > +struct S
> > +{
> > + tf m_fn1;
> > +} a;
> > +
> > +void
> > +fn1 ()
> > +{
> > + try
> > + {
> > + __builtin_va_list c;
> > + {
> > + int *d = __builtin_va_arg (c, int *);
> > + int **e = &d;
> > + __asm__("" : "=d"(e));
> > + a.m_fn1 ();
> > + }
> > + a.m_fn1 ();
> > + }
> > + catch (...)
> > + {
> > +
> > + }
> > +}
> > --
> > 1.9.1
> >
>
>
--
Richard Biener <rguenther@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Jennifer Guild,
Dilip Upmanyu, Graham Norton HRB 21284 (AG Nuernberg)