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Re: Minor improvement when adding call-clobbered symbols
- From: "Daniel Berlin" <dberlin at dberlin dot org>
- To: "Diego Novillo" <dnovillo at redhat dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Sun, 4 Mar 2007 18:24:32 -0500
- Subject: Re: Minor improvement when adding call-clobbered symbols
- References: <45E87891.firstname.lastname@example.org>
On 3/2/07, Diego Novillo <email@example.com> wrote:
If a memory tag T is call-clobbered, the operand scanner will blindly
add *all* the members of T's alias set to every call-site, regardless of
their individual clobbered state.
I assume the only case this really matters is when we partition,
because compute_call_clobbered should mark all aliases of a clobbered
tag as themselves clobbered, unless they are unmodifiable_var_p.
(see compute_call_clobbered and mark_aliases_call_clobbered)
Thus, without partitioning, the only clobberings this should save you
are unmodifiable_var_p clobbers, or something is broken :)
This patch fixes that. It should not give a huge improvement, but it
happens in some places. Bootstrapped and tested x86, x86-64, ia64 and i686.