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[AVR] changes zero_extendXXX2 instructions to 'define_insn_and_split'.

From: "Anatoly Sokolov" <aesok at post dot ru>
To: <gcc-patches at gcc dot gnu dot org>
Cc: <aesok at post dot ru>, <eweddington at cso dot atmel dot com>, <joerg_wunsch at uriah dot heep dot sax dot de>
Date: Fri, 6 Jul 2007 00:29:01 +0400
Subject: [AVR] changes zero_extendXXX2 instructions to 'define_insn_and_split'.

Hi.

  This patch changes zero_extendXXXX2 instructions pattern from 'define_insn'
to 'define_insn_and_split' and add zero_extendXXXX2 insn for DI mode. This
changes  allows  optimize 'CLR reg' instruction if the compiler knows that the
register already contains 0.  

  Code size reduction, in real word applications, approximately 1 instruction
for 2000. 

  No new regressions with this patch. Committed.

2007-07-05 Anatoly Sokolov <aesok@post.ru>

	* config/avr/avr.md (zero_extendqihi2, zero_extendqisi2, 
	zero_extendhisi2): Change to define_insn_and_split. 
	(zero_extendqidi2, zero_extendhidi2, zero_extendsidi2): New.

Anatoly.

Attachment: zero_extend.txt
Description: Text document

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