On Tue, Nov 06, 2012 at 02:35:30PM +0100, Jakub Jelinek wrote:
> On Tue, Nov 06, 2012 at 12:58:07AM +0100, Martin Jambor wrote:
> > 2012-11-05 Martin Jambor <mjam...@suse.cz>
> >
> > PR tree-optimization/53787
> > * ipa-cp.c (ipcp_value_source): New field offset.
> ...
>
> Is this supposed to do something about Fortran array descriptors
> where some fields in the descriptors have known constant values in the
> caller?
>
> Say
> subroutine bar (a, b, n)
> integer :: a(n), b(n)
> call foo (a, b)
> contains
> subroutine foo (a, b)
> integer :: a(:), b(:)
> a = b
> end subroutine
> end
> -O2 -fno-inline (there could be thousands of better testcases though, this
> one doesn't look at too many fields).
> With your patch
> foo.1899.constprop.0 is created, but I don't see any immediate other
> effects. Certainly e.g.
> _2 = a_1(D)->dim[0].stride;
> if (_2 != 0)
> remains till *.optimized dump, even when in the caller it is set to 1.
> I guess for Fortran being able to optimize on constant (or even better
> constant one) stride would be very worthwhile.
>
Oh... but that is not a due to a bug in this patch but due to an
unnecessarily strict bail out condition when building the jump
functions (code that went in in July), a thinko really. The following
patch fixes it. So far it is untested but I'll give it a go when
another bootstrap finishes. I'm not sure if it would be OK to commit
it now, given it is stage3, though. OTOH, I think it would be worth
it.
Thanks,
Martin
2012-11-07 Martin Jambor <mjam...@suse.cz>
* ipa-prop.c (determine_known_aggregate_parts): Skip writes to
different declarations when tracking writes to a declaration.
Index: src/gcc/ipa-prop.c
===================================================================
--- src.orig/gcc/ipa-prop.c
+++ src/gcc/ipa-prop.c
@@ -1318,7 +1318,12 @@ determine_known_aggregate_parts (gimple
break;
}
else if (lhs_base != arg_base)
- break;
+ {
+ if (DECL_P (lhs_base))
+ continue;
+ else
+ break;
+ }
if (lhs_offset + lhs_size < arg_offset
|| lhs_offset >= (arg_offset + arg_size))
