From: Ian Lance Taylor <iant@google.com>
To: Mohamed Shafi <shafitvm@gmail.com>
Cc: Richard Henderson <rth@redhat.com>, GCC <gcc@gcc.gnu.org>
Subject: Re: How to write shift and add pattern?
Date: Fri, 06 Nov 2009 15:34:00 -0000 [thread overview]
Message-ID: <mcr3a4r1xcp.fsf@dhcp-172-17-9-151.mtv.corp.google.com> (raw)
In-Reply-To: <ba0bd44d0911060529r5f6b9a3al83a8dea954a836a5@mail.gmail.com> (Mohamed Shafi's message of "Fri\, 6 Nov 2009 18\:59\:38 +0530")
Mohamed Shafi <shafitvm@gmail.com> writes:
> It is generating with data registers. Here is the pattern that i have
> written:
>
>
> (define_insn "*saddl"
> [(set (match_operand:SI 0 "register_operand" "=r,d")
> (plus:SI (mult:SI (match_operand:SI 1 "register_operand" "r,d")
> (match_operand:SI 2 "const24_operand" "J,J"))
> (match_operand:SI 3 "register_operand" "0,0")))]
>
> How can i do this. Will the constraint modifiers '?' or '!' help?
> How can make GCC generate shift and add sequence when the shift count is 1?
Does 'd' represent a data register? I assume that 'r' is a general
register, as it always is. What is the constraint character for an
address register? You don't seem to have an alternative here for
address registers, so I'm not surprised that the compiler isn't
picking it. No doubt I misunderstand something.
Ian
next prev parent reply other threads:[~2009-11-06 15:34 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-28 19:56 Mohamed Shafi
2009-08-28 23:49 ` Richard Henderson
2009-11-06 13:30 ` Mohamed Shafi
2009-11-06 15:34 ` Ian Lance Taylor [this message]
2009-11-09 12:53 ` Mohamed Shafi
2009-11-09 15:26 ` Ian Lance Taylor
2009-11-06 16:17 ` Richard Henderson
2009-11-09 12:49 ` Mohamed Shafi
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