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Re: [PATCH] gen_lowpart and lvalues

From: Richard Henderson <rth at redhat dot com>
To: Roger Sayle <roger at eyesopen dot com>
Cc: Eric Botcazou <ebotcazou at adacore dot com>, gcc-patches at gcc dot gnu dot org
Date: Thu, 24 Feb 2005 13:28:22 -0800
Subject: Re: [PATCH] gen_lowpart and lvalues
References: <200502240853.31317.ebotcazou@adacore.com> <Pine.LNX.4.44.0502241045350.9232-100000@www.eyesopen.com>

On Thu, Feb 24, 2005 at 12:38:43PM -0700, Roger Sayle wrote:
> But I do also agree that we should more clearly document that gen_lowpart
> doesn't preserve the lvalueness of it's operand, and that modifying
> the rtx returned from that function might/need not affect the value held
> by the argument rtx.

I do NOT agree to this.  There are way way too many users that do in
fact assume this, because for a long time it has been true.

If you want to make this true, then remove gen_lowpart completely and
replace all users with one of our many other subreg/lowpart generating
functions.

r~

Follow-Ups:
- Re: [PATCH] gen_lowpart and lvalues
  - From: Roger Sayle

References:
- [PATCH] gen_lowpart and lvalues
  - From: Eric Botcazou
- Re: [PATCH] gen_lowpart and lvalues
  - From: Roger Sayle

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