From: Hans-Peter Nilsson <hp@bitrange.com>
To: Richard Earnshaw <rearnsha@arm.com>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [patch][ARM] Fix 16-bit -> 64-bit multiply and accumulate
Date: Wed, 09 Feb 2011 06:31:00 -0000 [thread overview]
Message-ID: <alpine.BSF.2.00.1102090114520.65587@dair.pair.com> (raw)
In-Reply-To: <1296223929.9738.30.camel@e102346-lin.cambridge.arm.com>
On Fri, 28 Jan 2011, Richard Earnshaw wrote:
> Canonical RTL is not just about the order of the operands its about not
> having multiple ways of representing the same operation. Order is part
> of that, but not the end of it. For example, the canonical form of
>
> (lt:SI (reg:SI) (const_int 0))
>
> is
> (lshiftrt:SI (reg:SI) (const_int 31))
I kind of doubt that's canon. At least it shouldn't be that
way, except as a variant attempted by combine.
If so, ISTM i'd be a complicating factor for the cmpM patterns
of most ports. :) (Likewise unnamed variants for combine.)
brgds, H-P
prev parent reply other threads:[~2011-02-09 6:31 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-09 16:45 Andrew Stubbs
2011-01-27 2:09 ` Ramana Radhakrishnan
2011-01-27 10:46 ` Andrew Stubbs
2011-01-27 19:22 ` Richard Earnshaw
2011-01-28 13:06 ` Andrew Stubbs
2011-01-28 15:08 ` Richard Earnshaw
2011-01-28 15:55 ` Andrew Stubbs
2011-01-28 16:01 ` Richard Earnshaw
2011-03-25 16:27 ` Andrew Stubbs
2011-04-15 11:23 ` Andrew Stubbs
2011-05-03 9:08 ` Bernd Schmidt
2011-05-03 9:36 ` Andrew Stubbs
2011-05-18 15:32 ` [patch][combine] " Andrew Stubbs
2011-05-19 13:06 ` Bernd Schmidt
2011-05-24 17:51 ` [patch][simplify-rtx] " Andrew Stubbs
2011-05-24 21:00 ` Joseph S. Myers
2011-05-25 9:47 ` Andrew Stubbs
2011-05-25 12:34 ` Joseph S. Myers
2011-05-25 13:42 ` Andrew Stubbs
2011-05-25 13:48 ` Joseph S. Myers
2011-05-25 14:01 ` Andrew Stubbs
2011-05-25 14:27 ` Joseph S. Myers
2011-05-26 13:57 ` Andrew Stubbs
2011-05-26 14:47 ` Joseph S. Myers
2011-06-02 9:46 ` Richard Earnshaw
2011-06-07 11:05 ` Andrew Stubbs
2011-02-09 6:31 ` Hans-Peter Nilsson [this message]
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