[PATCH] Fix for PR64353

[Richard Biener]

On January 14, 2015 5:23:21 PM CET, Ilya Enkovich <enkovich.gnu@gmail.com> wrote:
>On 14 Jan 15:35, Richard Biener wrote:
>> On Wed, Jan 14, 2015 at 3:28 PM, Ilya Enkovich
><enkovich.gnu@gmail.com> wrote:
>> > Hi,
>> >
>> > SRA gimple passes may add loads to functions with no SSA update. 
>Later it causes ICE when function with not updated SSA is processed by
>gimple passes.  This patch fixes it by calling update_ssa.
>> >
>> > Bootstrapped and checked on x86_64-unknown-linux-gnu.  OK for
>trunk?
>> 
>> No.  I have removed this quadratic update-ssa call previously.  It
>should
>> simply keep SSA for up-to-date manually (see how it does
>gimple_set_vuse
>> in some cases, probably not all required ones?).
>> 
>
>Would it be OK to call update_ssa only in case we don't have a proper
>VUSE for call? 

No, and most definitely not here.


Are we allowed to just emit error due to incorrect
>attribute?

No, I don't think so either. But we may drop it.

Richard.

>
>diff --git a/gcc/ipa-prop.c b/gcc/ipa-prop.c
>index 01f4111..4ce7822 100644
>--- a/gcc/ipa-prop.c
>+++ b/gcc/ipa-prop.c
>@@ -4054,6 +4054,11 @@ ipa_modify_call_arguments (struct cgraph_edge
>*cs, gcall *stmt,
> 		    expr = create_tmp_reg (TREE_TYPE (expr));
> 		  gimple_assign_set_lhs (tem, expr);
> 		  gsi_insert_before (&gsi, tem, GSI_SAME_STMT);
>+		  /* In case callee has a wrong __attribute__((const))
>+		     we may have no VUSE for the call and thus require
>+		     SSA update for the inserted load.  See PR64353.  */
>+		  if (gimple_in_ssa_p (cfun) && !gimple_vuse (stmt))
>+		    update_ssa (TODO_update_ssa_only_virtuals);
> 		}
> 	    }
> 	  else
>
>Thanks,
>Ilya
>
>> Richard.
>> 
>> > Thanks,
>> > Ilya
>> > --
>> > gcc/
>> >
>> > 2015-01-14  Ilya Enkovich  <ilya.enkovich@intel.com>
>> >
>> >         PR middle-end/64353
>> >         * ipa-prop.c (ipa_modify_call_arguments): Update SSA for
>> >         vops after adding a load.
>> >
>> >
>> > gcc/testsuite/
>> >
>> > 2015-01-14  Ilya Enkovich  <ilya.enkovich@intel.com>
>> >
>> >         PR middle-end/64353
>> >         * g++.dg/pr64353.C: New.
>> >
>> >
>> > diff --git a/gcc/ipa-prop.c b/gcc/ipa-prop.c
>> > index 01f4111..533dcfe 100644
>> > --- a/gcc/ipa-prop.c
>> > +++ b/gcc/ipa-prop.c
>> > @@ -4054,6 +4054,8 @@ ipa_modify_call_arguments (struct cgraph_edge
>*cs, gcall *stmt,
>> >                     expr = create_tmp_reg (TREE_TYPE (expr));
>> >                   gimple_assign_set_lhs (tem, expr);
>> >                   gsi_insert_before (&gsi, tem, GSI_SAME_STMT);
>> > +                 if (gimple_in_ssa_p (cfun))
>> > +                   update_ssa (TODO_update_ssa_only_virtuals);
>> >                 }
>> >             }
>> >           else
>> > diff --git a/gcc/testsuite/g++.dg/pr64353.C
>b/gcc/testsuite/g++.dg/pr64353.C
>> > new file mode 100644
>> > index 0000000..7859918
>> > --- /dev/null
>> > +++ b/gcc/testsuite/g++.dg/pr64353.C
>> > @@ -0,0 +1,15 @@
>> > +/* { dg-do compile } */
>> > +/* { dg-options "-O2" } */
>> > +
>> > +class C
>> > +{
>> > +  int y, x;
>> > +  void i ();
>> > +  bool __attribute__((const)) xx () { return x; }
>> > +};
>> > +
>> > +void C::i ()
>> > +{
>> > +  if (xx ())
>> > +    x = 1;
>> > +}