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Re: Incorrect bitfield aliasing with Tree SSA
- From: Eric Botcazou <ebotcazou at libertysurf dot fr>
- To: Richard Kenner <kenner at vlsi1 dot ultra dot nyu dot edu>
- Cc: anemet at caviumnetworks dot com, dberlin at dberlin dot org, gcc-patches at gcc dot gnu dot org
- Date: Tue, 19 Jun 2007 16:19:24 +0200
- Subject: Re: Incorrect bitfield aliasing with Tree SSA
- References: <18034.48960.772642.116034@localhost.localdomain> <18039.29800.223240.870336@localhost.localdomain> <10706191348.AA08767@vlsi1.ultra.nyu.edu>
> Do you need this extra memory? Can't you just have a flag that says
> to look at TYPE_ALIAS_SET (DECL_CONTEXT (field))?
Yes, that would indeed be better.
Adam, would it be feasible to add a flag to tree_memory_tag instead?
struct tree_memory_tag GTY(())
{
struct tree_decl_minimal common;
bitmap GTY ((skip)) aliases;
unsigned int is_global:1;
};
struct tree_struct_field_tag GTY(())
{
struct tree_memory_tag common;
/* Parent variable. */
tree parent_var;
/* Offset inside structure. */
unsigned HOST_WIDE_INT offset;
/* Size of the field. */
unsigned HOST_WIDE_INT size;
};
And use parent_var to fetch the alias set somehow?
--
Eric Botcazou