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.
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
