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Re: Patch ping (1 middle-end, 1 C front-end)
- From: Roger Sayle <roger at eyesopen dot com>
- To: Bonzini <bonzini at gnu dot org>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Tue, 16 Mar 2004 05:51:55 -0700 (MST)
- Subject: Re: Patch ping (1 middle-end, 1 C front-end)
On Tue, 16 Mar 2004, Bonzini wrote:
> Remove a parameter from combine_simplify_rtx (very short)
This is OK for mainline. However you need to update the comments
above combine_simplify_rtx and simplify_logical now that you've
removed their LAST parameter. Approved with those changes.
Ideally, I think it would be preferrable to add an additional
check to the problematic "(ior (and X C1) C2)" optimization,
to only perform this transformation if
(INTVAL (XEXP (op0, 1)) & INTVAL (op1)) != 0
i.e. avoid calling "gen_binary" if the expression is unchanged.
If we were ever to replace these calls with simplify_gen_binary
we could potentially end-up with unbounded recursion. This
might be one of the original reasons for this "last" parameter,
it also helps typical case performance and memory usage.