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Re: [PATCH] fix hardreg_cprop to honor HARD_REGNO_MODE_OK.

From: Jeff Law <law at redhat dot com>
To: Ilya Tocar <tocarip dot intel at gmail dot com>, gcc-patches at gcc dot gnu dot org
Date: Wed, 13 Aug 2014 14:31:18 -0600
Subject: Re: [PATCH] fix hardreg_cprop to honor HARD_REGNO_MODE_OK.
Authentication-results: sourceware.org; auth=none
References: <20140811134937 dot GA95937 at msticlxl7 dot ims dot intel dot com>

On 08/11/14 07:49, Ilya Tocar wrote:

Hi,

I've observed SPEC2006 failure on avx512-vlbwdq branch.
It was caused by  hardreg_cprop. In maybe_mode_change it was
assumed, that all values of the same register class and same mode.
are ok. This is not the case for i386/avx512. We need to honor
HARD_REGNO_MODE_OK.
Patch bellow does it.
Ok for trunk?

2014-08-11  Ilya Tocar  <ilya.tocar@intel.com>

	* regcprop.c (maybe_mode_change): Honor HARD_REGNO_MODE_OK.

One could argue that having a class where some members are OK for beingused in a particular mode, but other members are not is the core issuehere.

Can you describe a bit about why you've got a class of that nature?Background on that would be useful.


jeff

Follow-Ups:
- Re: [PATCH] fix hardreg_cprop to honor HARD_REGNO_MODE_OK.
  - From: Ilya Tocar

References:
- [PATCH] fix hardreg_cprop to honor HARD_REGNO_MODE_OK.
  - From: Ilya Tocar

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