Re: [PATCH] Fix PR 54494, removal of volatile store in strlen optimization because of the inlininer

[Andrew Pinski <pinskia at gmail dot com>]

On Thu, Sep 6, 2012 at 12:07 AM, Jakub Jelinek <jakub@redhat.com> wrote:
> On Wed, Sep 05, 2012 at 09:10:53PM -0700, Andrew Pinski wrote:
>>   The inlininer likes to recreate some MEM_REF, it copies most of the
>> bits (TREE_THIS_NOTRAP, TREE_THIS_VOLATILE, etc.) but forgets about
>> TREE_SIDE_EFFECTS.  This causes the strlen optimization to think the
>> memory store does not have a side effects.
>>
>> OK?  Bootstrapped and tested on x86_64-linux-gnu with no regressions.
>>
>> Thanks,
>> Andrew Pinski
>>
>> ChangeLog:
>>
>> * tree-inline.c (remap_gimple_op_r): Copy TREE_SIDE_EFFECTS also.
>>
>> testsuite/ChangeLog:
>> * gcc.dg/tree-ssa/strlen-1.c: New testcase.
>
> Patch preapproved, but you've attached a different patch.

Sorry about that.  Here is the correct one.

Also is this ok for the 4.7 branch?

Thanks,
Andrew Pinski

>
> I'd say copy_tree_body_r's MEM_REF handling should also copy
> TREE_SIDE_EFFECTS/TREE_THIS_NOTRAP (what about TREE_READONLY?),
> maybe copy_decl_to_var/copy_result_decl_to_var should also
> copy TREE_SIDE_EFFECTS, perhaps omp-low.c copy_var_decl, install_var_field,
> tree-nested.c lookup_field_for_decl, tree-sra.c sra_ipa_reset_debug_stmts
> (grep TREE_THIS_VOLATILE.*TREE_THIS_VOLATILE, looking for missing
> TREE_SIDE_EFFECTS copy nearby).  That said, perhaps the tree-ssa-strlen.c
> change is desirable too, unless we add some checking that TREE_THIS_VOLATILE
> references/decls have TREE_SIDE_EFFECTS bit set in the IL.
>
>> --- testsuite/gcc.c-torture/compile/pr49474.c (revision 0)
>> +++ testsuite/gcc.c-torture/compile/pr49474.c (revision 0)
>> --- cprop.c   (revision 176187)
>> +++ cprop.c   (working copy)
>
>         Jakub

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