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Re: memrefs_conflict_p () for REGs in alias.c
- From: George H <grgh007 at yahoo dot com>
- To: Richard Henderson <rth at redhat dot com>
- Cc: gcc at gcc dot gnu dot org
- Date: Thu, 3 Oct 2002 02:41:44 -0700 (PDT)
- Subject: Re: memrefs_conflict_p () for REGs in alias.c
> > I found that it always returns 1 for cse in case
> > of REG...
>
> Yes. alias.c computes function invariants. If a
> register
> is set more than once, it varies, and thus there is
> no data
> on what it points to.
>
>
> r~
The only point I wanted to indicate is that there
seems to be no way of determining whether the
addresses contained in two REGs may be distinct.
e.g. base_alias_check () *only compares the base
addresses* of two REGs and assumes aliasing if they
match.
The mechanism to know how the addresses in two REGs
have been computed is missing, which may help in
distinguishing the addresses.
-gh
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