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Re: ia32: check_decr_loop
- To: Richard Henderson <rth@cygnus.com>
- Subject: Re: ia32: check_decr_loop
- From: Bernd Schmidt <bernds@cygnus.co.uk>
- Date: Tue, 10 Aug 1999 14:48:58 +0100 (BST)
- cc: gcc-patches@gcc.gnu.org
>
> + /* Look for loops of the form
> + while (a--) { ... }
> + where a is not used inside the loop, and optimize them. */
>
> It was implemented to get a few percent on a tiny loop on a benchmark.
> It seems somewhat silly, except to my surprise the optimization is
> triggered occasionally by real code too -- three times in cc1 itself.
I'm not sure whether it is worthwhile to add several hundred lines of code
for an optimization that triggers only three times in a large program. How
big are the gains - anything measurable?
Bernd