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Re: Partial fix for PR opt/55177

From: Jeff Law <law at redhat dot com>
To: Eric Botcazou <ebotcazou at adacore dot com>
Cc: gcc-patches at gcc dot gnu dot org, Andrew Pinski <pinskia at gmail dot com>
Date: Thu, 23 May 2013 10:48:30 -0600
Subject: Re: Partial fix for PR opt/55177
References: <1670912 dot nR7bjsZv4e at polaris>

On 05/23/2013 10:05 AM, Eric Botcazou wrote:

The PR is about missed simplifications for __builtin_swap.  IIUC Andrew has
patches for them at the Tree level, but I think having basic simplifications
at the RTL level for BSWAP is also worthwhile, hence the attached patch.

Tested on x86_64-suse-linux.  Comments?


2013-05-23  Eric Botcazou  <ebotcazou@adacore.com>

	PR opt/55177
	* simplify-rtx.c (simplify_unary_operation_1) <NOT>: Deal with BSWAP.
	(simplify_byte_swapping_operation): New.
	(simplify_binary_operation_1): Call it for AND, IOR and XOR.
	(simplify_relational_operation_1): Deal with BSWAP.


2013-05-23  Eric Botcazou  <ebotcazou@adacore.com>

	* gcc.dg/builtin-bswap-6.c: New test.
	* gcc.dg/builtin-bswap-7.c: Likewise.
	* gcc.dg/builtin-bswap-8.c: Likewise.
	* gcc.dg/builtin-bswap-9.c: Likewise.

Seems reasonable. And no matter how hard we try, just about everythingwe want to catch at the tree level will by some path be exposable at theRTL level as well.

I'd like to see the gimple equivalents moving forward as well, butrealize you may not be in a position to move Andrew's code forward.


Jeff

References:
- Partial fix for PR opt/55177
  - From: Eric Botcazou

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