From: Richard Earnshaw <rearnsha@arm.com>
To: Andrew Stubbs <ams@codesourcery.com>
Cc: "gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>,
"patches@linaro.org" <patches@linaro.org>
Subject: Re: [PATCH][ARM] NEON DImode neg
Date: Mon, 16 Apr 2012 12:42:00 -0000 [thread overview]
Message-ID: <4F8C138B.6090309@arm.com> (raw)
In-Reply-To: <4F897794.7010402@codesourcery.com>
On 14/04/12 14:11, Andrew Stubbs wrote:
> And now with the patch. :(
>
> On 14/04/12 13:48, Andrew Stubbs wrote:
>> On 12/04/12 16:48, Richard Earnshaw wrote:
>>> If negation in Neon needs a scratch register, it seems to me to be
>>> somewhat odd that we're disparaging the ARM version.
>>>
>>> Also, wouldn't it be sensible to support a variant that was
>>> early-clobber on operand 0, but loaded immediate zero into that value
>>> first:
>>>
>>> vmov Dd, #0
>>> vsub Dd, Dd, Dm
>>>
>>> That way you'll never need more than two registers, whereas today you
>>> want three.
>>
>> This patch implements the changes you suggested.
>>
>> I've done a full bootstrap and test and found no regressions.
>>
>> OK?
>>
>> Andrew
>>
>> P.S. This patch can't actually be committed until my "NEON DImode
>> immediate constants" patch is approved and committed. (Without that the
>> load #0 needs a constant pool, and loading constants this late has a bug
>> at -O0.)
>>
>> neon-neg64.patch
>>
>>
>> 2012-04-12 Andrew Stubbs <ams@codesourcery.com>
>>
>> gcc/
>> * config/arm/arm.md (negdi2): Use gen_negdi2_neon.
>> * config/arm/neon.md (negdi2_neon): New insn.
>> Also add splitters for core and NEON registers.
>>
OK
R.
next prev parent reply other threads:[~2012-04-16 12:42 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-28 19:53 Andrew Stubbs
2012-02-29 14:44 ` Andrew Stubbs
2012-03-26 10:14 ` Andrew Stubbs
2012-04-12 14:57 ` Andrew Stubbs
2012-04-12 15:48 ` Richard Earnshaw
2012-04-12 16:17 ` Andrew Stubbs
2012-04-12 16:43 ` Richard Earnshaw
2012-04-14 12:49 ` Andrew Stubbs
2012-04-14 13:12 ` Andrew Stubbs
2012-04-16 12:42 ` Richard Earnshaw [this message]
2012-04-30 14:13 ` Andrew Stubbs
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