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Re: addsi3 with set condition register

From: David Edelsohn <dje at watson dot ibm dot com>
To: ibanez at sunplus dot com
Cc: gcc at gcc dot gnu dot org
Date: Thu, 14 Jul 2005 09:34:27 -0400
Subject: Re: addsi3 with set condition register
References: <OF93EDB1FA.00C74791-ON4825703E.0037A250-4825703E.0037A25E@sunplus.com>

>>>>> ibanez  writes:

ibanez> 2.)
ibanez> add_c   <-  add & update condition register

ibanez> But case 2 pattern is not used at all.

ibanez> (define_insn "..."
ibanez> [ (set (match_operand:SI 0 "register_operand" "=g")
ibanez> (plus:SI (match_operand:SI 1 "register_operand" "g")
ibanez> (match_operand:SI 2 "register_operand" "g")) )
ibanez> (set
ibanez> (reg:CC CC_REGNUM)
ibanez> (compare:CC (match_dup 0) (const_int 0)))]

	Try listing the compare first.  Also, you might try listing the
compare register as a match_operand with a constraint for the CC register
instead of hard-coding the register.  See rs6000.md add<mode>3_internal2
and add<mode>3_internal3 patterns for examples.

David

References:
- addsi3 with set condition register
  - From: ibanez

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