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Re: [PATCH, rtl-optimization]: Fix PR54457, [x32] Fail to combine 64bit index + constant

From: Eric Botcazou <ebotcazou at adacore dot com>
To: Richard Sandiford <rdsandiford at googlemail dot com>
Cc: gcc-patches at gcc dot gnu dot org, Uros Bizjak <ubizjak at gmail dot com>
Date: Wed, 26 Sep 2012 23:22:14 +0200
Subject: Re: [PATCH, rtl-optimization]: Fix PR54457, [x32] Fail to combine 64bit index + constant
References: <CAFULd4bHjvbiX-eB1sh339Z1dZeaFn32_wjdu7VOQySn0fey4Q@mail.gmail.com> <877grgu0yt.fsf@talisman.home>

> 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?

-- 
Eric Botcazou

Follow-Ups:
- Re: [PATCH, rtl-optimization]: Fix PR54457, [x32] Fail to combine 64bit index + constant
  - From: Uros Bizjak

References:
- [PATCH, rtl-optimization]: Fix PR54457, [x32] Fail to combine 64bit index + constant
  - From: Uros Bizjak
- Re: [PATCH, rtl-optimization]: Fix PR54457, [x32] Fail to combine 64bit index + constant
  - From: Richard Sandiford

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