From: Jeff Law <law@redhat.com>
To: Bernd Schmidt <bernds@codesourcery.com>
Cc: GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH 5/6] Generate more shrink-wrapping opportunities
Date: Wed, 23 Mar 2011 15:03:00 -0000 [thread overview]
Message-ID: <4D8A0BC2.7070901@redhat.com> (raw)
In-Reply-To: <4D8A09E5.7070105@codesourcery.com>
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On 03/23/11 08:55, Bernd Schmidt wrote:
> The first basic block contains insns to move incoming argument registers
> to pseudos. When these pseudos live across calls, they get allocated to
> call-saved registers. This in turns disables shrink-wrapping, since the
> move instruction requires the prologue (saving the call-saved reg) to
> occur before it.
>
> This patch addresses the problem by moving such moves downwards through
> the CFG until we find a place where the destination is used or the
> incoming argument is clobbered.
FWIW, downward motion of the moves out of arg registers (or loads from
arg slots) is definitely a good thing. This was a regular source of
unnecessary register pressure leading to spills in codes I've looked at.
I hope your sinking code works better than the quick and dirty one I
wrote but never contributed.
jeff
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next prev parent reply other threads:[~2011-03-23 15:03 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-23 14:44 Shrink-wrapping: Introduction Bernd Schmidt
2011-03-23 14:46 ` [PATCH 1/6] Disallow predicating the prologue Bernd Schmidt
2011-03-31 13:20 ` Jeff Law
2011-04-01 18:59 ` H.J. Lu
2011-04-01 21:08 ` Bernd Schmidt
2011-03-23 14:48 ` [PATCH 2/6] Unique return rtx Bernd Schmidt
2011-03-31 13:23 ` Jeff Law
2011-05-03 11:54 ` Bernd Schmidt
2011-03-23 14:51 ` [PATCH 3/6] Allow jumps in epilogues Bernd Schmidt
2011-03-23 16:46 ` Richard Henderson
2011-03-23 16:49 ` Bernd Schmidt
2011-03-23 17:19 ` Richard Henderson
2011-03-23 17:24 ` Bernd Schmidt
2011-03-23 17:27 ` Richard Henderson
2011-03-24 10:30 ` Bernd Schmidt
2011-03-25 17:51 ` Bernd Schmidt
2011-03-26 5:33 ` Richard Henderson
2011-03-31 20:09 ` Bernd Schmidt
2011-03-31 21:51 ` Richard Henderson
2011-03-31 22:36 ` Bernd Schmidt
2011-03-31 23:57 ` Richard Henderson
2011-04-05 21:59 ` Bernd Schmidt
2011-04-11 17:10 ` Richard Henderson
2011-04-13 14:16 ` Bernd Schmidt
2011-04-13 15:14 ` Bernd Schmidt
2011-04-13 15:16 ` Bernd Schmidt
2011-04-13 15:17 ` Bernd Schmidt
2011-04-13 15:28 ` Bernd Schmidt
2011-04-13 14:44 ` Richard Henderson
2011-04-13 14:54 ` Jakub Jelinek
2011-04-15 16:29 ` Bernd Schmidt
2011-03-23 14:56 ` [PATCH 5/6] Generate more shrink-wrapping opportunities Bernd Schmidt
2011-03-23 15:03 ` Jeff Law [this message]
2011-03-23 15:05 ` Bernd Schmidt
2011-03-23 15:18 ` Jeff Law
2011-03-31 13:26 ` Jeff Law
2011-03-31 13:34 ` Bernd Schmidt
2011-03-23 14:56 ` [PATCH 4/6] Shrink-wrapping Bernd Schmidt
2011-07-07 14:51 ` Richard Sandiford
2011-07-07 15:40 ` Bernd Schmidt
2011-07-07 17:00 ` Paul Koning
2011-07-07 17:02 ` Jeff Law
2011-07-07 17:05 ` Paul Koning
2011-07-07 17:08 ` Jeff Law
2011-07-07 17:30 ` Bernd Schmidt
2011-07-08 22:59 ` [pdp11] Emit prologue as rtl Richard Henderson
2011-07-09 13:46 ` Paul Koning
2011-07-09 16:53 ` Richard Henderson
2011-07-07 15:57 ` [PATCH 4/6] Shrink-wrapping Richard Earnshaw
2011-07-07 20:19 ` Richard Sandiford
2011-07-08 8:30 ` Richard Earnshaw
2011-07-08 13:57 ` Bernd Schmidt
2011-07-11 11:24 ` Richard Sandiford
2011-07-11 11:42 ` Bernd Schmidt
2011-07-21 3:57 ` Bernd Schmidt
2011-07-21 11:25 ` Richard Sandiford
2011-07-28 11:48 ` Bernd Schmidt
2011-07-28 12:45 ` Richard Sandiford
2011-07-28 23:30 ` Richard Earnshaw
2011-07-29 12:40 ` Bernd Schmidt
2011-08-03 10:42 ` Alan Modra
2011-08-03 11:19 ` Bernd Schmidt
2011-08-02 8:40 ` Bernd Schmidt
2011-08-03 15:39 ` Richard Sandiford
2011-08-24 19:23 ` Bernd Schmidt
2011-08-24 20:48 ` Richard Sandiford
2011-08-24 20:55 ` Bernd Schmidt
2011-08-26 14:49 ` Ramana Radhakrishnan
2011-08-26 14:58 ` Bernd Schmidt
2011-08-26 15:06 ` Ramana Radhakrishnan
2011-08-28 10:58 ` H.J. Lu
2011-07-07 21:41 ` Michael Hope
2011-03-23 14:57 ` [PATCH 6/6] A testcase Bernd Schmidt
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