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From: <Paul_Koning@Dell.com>
To: <ubizjak@gmail.com>
Cc: <gcc-patches@gcc.gnu.org>, <rdsandiford@googlemail.com>,
	<ebotcazou@adacore.com>
Subject: Re: [PATCH v2, rtl-optimization]: Fix PR54457, [x32] Fail to combine 64bit index + constant
Date: Thu, 27 Sep 2012 18:35:00 -0000	[thread overview]
Message-ID: <C75A84166056C94F84D238A44AF9F6AD237AC0@AUSX10MPS303.AMER.DELL.COM> (raw)
In-Reply-To: <CAFULd4YiqSJPDNzg3XTyWx=mBphzCWSpuaQiQ7SbO17Bgc7SSA@mail.gmail.com>


On Sep 27, 2012, at 2:04 PM, Uros Bizjak wrote:

> 
> 
> 
>>>>> I agree (subreg:M (op:N A C) 0) to (op:M (subreg:N (A 0)) C) is
>>>>> a good transformation, but why do we need to handle as special
>>>>> the case where the subreg is itself the operand of a plus or minus?
>>>>> I think it should happen regardless of where the subreg occurs.
>>>> 
>>>> Don't we need to restrict this to the low part though?
>>> 
>>> ...
> 
> After some off-line discussion with Richard, attached is v2 of the patch.
> 
> 2012-09-27  Uros Bizjak  <ubizjak@gmail.com>
> 
>        PR rtl-optimization/54457
>        * simplify-rtx.c (simplify_subreg):
> 	Simplify (subreg:SI (op:DI ((x:DI) (y:DI)), 0)
>     	to (op:SI (subreg:SI (x:DI) 0) (subreg:SI (x:DI) 0)).
> ...

Is it just specific to DI -> SI, or is it for any large mode -> smaller mode, like SI -> HI?

	paul


  reply	other threads:[~2012-09-27 18:08 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-25  8:04 [PATCH, " Uros Bizjak
2012-09-26 18:17 ` Richard Sandiford
2012-09-26 21:38   ` Eric Botcazou
2012-09-27 14:25     ` Uros Bizjak
2012-09-27 16:10       ` Richard Sandiford
2012-09-27 18:20         ` [PATCH v2, " Uros Bizjak
2012-09-27 18:35           ` Paul_Koning [this message]
2012-09-27 19:21             ` Uros Bizjak
2012-10-02  2:13               ` Andrew Pinski
2012-10-02 19:32                 ` Richard Sandiford
2012-10-06 10:22                   ` RFA: Simplifying truncation and integer lowpart subregs Richard Sandiford
2012-10-06 11:13                     ` Eric Botcazou
2012-10-06 12:39                       ` Richard Sandiford
2012-10-06 13:05                         ` Eric Botcazou
2012-10-07  8:56                           ` Richard Sandiford
2012-10-07 12:36                             ` Eric Botcazou
2012-11-28  2:27                             ` Ramana Radhakrishnan
2012-11-28 21:45                               ` Richard Sandiford
2012-09-27 20:33           ` [PATCH v2, rtl-optimization]: Fix PR54457, [x32] Fail to combine 64bit index + constant Jakub Jelinek
2012-09-27 22:37             ` Richard Sandiford
2012-09-28 15:39             ` Uros Bizjak
2012-09-30 11:40               ` Richard Sandiford
2012-10-03 11:07                 ` Paolo Bonzini

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