From: Richard Sandiford <rdsandiford@googlemail.com>
To: James Greenhalgh <james.greenhalgh@arm.com>
Cc: gcc-patches@gcc.gnu.org, gerald@pfeifer.com, joseph@codesourcery.com
Subject: Re: [Patch docs 4/5] Update "Output Template/Statement" from md.texi
Date: Mon, 12 Jan 2015 22:19:00 -0000 [thread overview]
Message-ID: <87wq4r8x93.fsf@googlemail.com> (raw)
In-Reply-To: <1420543302-11008-5-git-send-email-james.greenhalgh@arm.com> (James Greenhalgh's message of "Tue, 6 Jan 2015 11:21:41 +0000")
James Greenhalgh <james.greenhalgh@arm.com> writes:
> If the output control string starts with a @samp{@@}, then it is actually
> a series of templates, each on a separate line. (Blank lines and
> leading spaces and tabs are ignored.) The templates correspond to the
> -pattern's constraint alternatives (@pxref{Multi-Alternative}). For example,
> -if a target machine has a two-address add instruction @samp{addr} to add
> -into a register and another @samp{addm} to add a register to memory, you
> -might write this pattern:
> +pattern's constraint alternatives (@pxref{Multi-Alternative}).
> +
> +For example, if a target machine has a two-address add instruction
> +@samp{addreg} to add into a register and another @samp{addmem} to add
> +a register to memory, this pattern could be used to describe the
> +instructions.
>
> @smallexample
> (define_insn "addsi3"
> [(set (match_operand:SI 0 "general_operand" "=r,m")
> (plus:SI (match_operand:SI 1 "general_operand" "0,0")
> - (match_operand:SI 2 "general_operand" "g,r")))]
> + (match_operand:SI 2 "general_operand" "r,r")))]
> ""
> "@@
> - addr %2,%0
> - addm %2,%0")
> + addreg %2,%0
> + addmem %2,%0")
> @end smallexample
While there, I think we should tighten the predicates to
nonimmediate_operand for operands 0 and 1 and -- given the
new constraints -- register_operand for operand 2.
Thanks,
Richard
next prev parent reply other threads:[~2015-01-12 22:11 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-06 11:21 [Patch docs 0/5] Update some of md.texi James Greenhalgh
2015-01-06 11:22 ` [Patch docs 2/5] Update "Instruction Patterns" in md.texi James Greenhalgh
2015-01-08 22:00 ` Jeff Law
2015-01-09 2:19 ` Segher Boessenkool
2015-01-11 17:40 ` James Greenhalgh
2015-01-12 22:31 ` Richard Sandiford
2015-01-06 11:22 ` [Patch docs 3/5] Update "RTL Template" " James Greenhalgh
2015-01-12 22:04 ` Jeff Law
2015-01-12 22:11 ` Richard Sandiford
2015-01-06 11:22 ` [Patch docs 4/5] Update "Output Template/Statement" from md.texi James Greenhalgh
2015-01-12 21:46 ` Jeff Law
2015-01-12 22:19 ` Richard Sandiford [this message]
2015-01-06 11:22 ` [Patch docs 1/5] Update the first section of md.texi James Greenhalgh
2015-01-06 16:56 ` James Greenhalgh
2015-01-06 18:55 ` Joseph Myers
2015-01-08 21:43 ` Jeff Law
2015-01-09 2:11 ` Segher Boessenkool
2015-01-12 22:29 ` Richard Sandiford
2015-01-06 11:23 ` [Patch docs 5/5] Update "Predicates" from md.texi James Greenhalgh
2015-01-12 22:42 ` Richard Sandiford
2015-01-06 14:57 ` [Patch docs 0/5] Update some of md.texi Joseph Myers
2015-01-06 15:26 ` James Greenhalgh
2015-01-06 17:31 ` Sandra Loosemore
2015-01-06 18:46 ` Joseph Myers
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