Re: [patch] Fix PR bootstrap/58509

[Richard Biener <richard dot guenther at gmail dot com>]

On Fri, Sep 27, 2013 at 1:17 PM, Eric Botcazou <ebotcazou@adacore.com> wrote:
> Hi,
>
> this fixes the ICE during the build of the Ada runtime on the SPARC, a fallout
> of the recent inliner changes:
>   http://gcc.gnu.org/ml/gcc-patches/2013-09/msg01033.html
>
> The ICE is triggered because the ldd peephole merges an MEM with MEM_NOTRAP_P
> and a contiguous MEM without MEM_NOTRAP_P, keeping the MEM_NOTRAP_P flag on
> the result.  As a consequence, an EH edge is eliminated and a BB is orphaned.
>
> I think this shows that my above inliner patch was too gross: when you have
> successive inlining, you can quickly end up with a mess of trapping and non-
> trapping memory accesses for the same object.  So the attached seriously
> refines it, restricting it to parameters with reference type and leaning
> towards being less conservative.  Again, this should only affect Ada.
>
> Tested on x86_64-suse-linux, OK for the mainline?

This is getting somewhat gross ... what about clearing all TREE_NO_TRAPs
on inlining?

Otherwise I think the "proper" way is to teach passes that moving loads/stores
eventually has to clear TREE_NO_TRAP ... (a reason that for example
VRP cannot set TREE_NO_TRAP on dereferences of pointers that have
a non-NULL range...).

Richard.


> 2013-09-27  Eric Botcazou  <ebotcazou@adacore.com>
>
>         PR bootstrap/58509
>         * ipa-prop.h (get_ancestor_addr_info): Declare.
>         * ipa-prop.c (get_ancestor_addr_info): Make public.
>         * tree-inline.c (is_parm): Rename into...
>         (is_ref_parm): ...this.
>         (is_based_on_ref_parm): New predicate.
>         (remap_gimple_op_r): Do not propagate TREE_THIS_NOTRAP on MEM_REF if
>         a parameter with reference type has been remapped and the result is
>         not based on another parameter with reference type.
>         (copy_tree_body_r): Likewise on INDIRECT_REF and MEM_REF.
>
>
> 2013-09-27  Eric Botcazou  <ebotcazou@adacore.com>
>
>         * gnat.dg/specs/opt1.ads: New test.
>
>
> --
> Eric Botcazou