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Re: Find more shrink-wrapping opportunities
- From: Andrew Pinski <pinskia at gmail dot com>
- To: Bernd Schmidt <bernds at codesourcery dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 1 Dec 2011 18:47:56 -0800
- Subject: Re: Find more shrink-wrapping opportunities
- References: <4E8CC286.80107@codesourcery.com>
On Wed, Oct 5, 2011 at 1:48 PM, Bernd Schmidt <bernds@codesourcery.com> wrote:
> This adds a little mini-pass to shrink-wrapping, to eliminate a common
> case that often makes shrink-wrapping unavailable. If a move insn copies
> an argument registers to a call-saved register, the prologue must be
> emitted before this insn. We should therefore try to delay such moves
> for as long as possible.
>
> A followup patch will add an extra cprop pass, which replaces uses of
> the call-saved register with uses of the incoming argument register,
> thereby allowing us to move the copies in even more cases.
By the way the testcase in
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=10474 seems to the
testcase which needs the extra cprop pass to allow for shrink
wrapping.
Thanks,
Andrew Pinski