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Re: [PATCH] combine: Do not allow asm as I2 in a special case

From: Jeff Law <law at redhat dot com>
To: Segher Boessenkool <segher at kernel dot crashing dot org>, gcc-patches at gcc dot gnu dot org
Date: Wed, 10 Dec 2014 15:57:26 -0700
Subject: Re: [PATCH] combine: Do not allow asm as I2 in a special case
Authentication-results: sourceware.org; auth=none
References: <57fc8b78d95beca67e0f4146ea117aee4bf316dd dot 1418240878 dot git dot segher at kernel dot crashing dot org>

On 12/10/14 13:12, Segher Boessenkool wrote:

My rs6000 patch putting a clobber of the carry in every asm regressed
guality/pr41353-1.c.  This is because the asm (in f3 in that testcase,
for example) now is a PARALLEL, and the special case for I2 a parallel
and I3 a register move now triggers.  Before, when the asm was not a
parallel, can_combine_p disallowed combining I2.  The effect of the
change is that some debug info becomes invalid and is deleted later,
causing the testsuite regression.

Let's not allow combining an asm in this special case either.

Bootstrapped and tested on powerpc64-linux; okay for mainline?


Segher


2014-12-10  Segher Boessenkool  <segher@kernel.crashing.org>

gcc/
	* combine.c (try_combine): Do not allow combining a PARALLEL I2
	with a register move I3 if that I2 is an asm.

OK.
jeff

References:
- [PATCH] combine: Do not allow asm as I2 in a special case
  - From: Segher Boessenkool

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