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Re: [PATCH] #52291 - clarify sync_fetch_and_OP for pointers

From: Jeff Law <law at redhat dot com>
To: Martin Sebor <msebor at gmail dot com>, Gcc Patch List <gcc-patches at gcc dot gnu dot org>
Date: Wed, 20 Jan 2016 19:48:05 -0700
Subject: Re: [PATCH] #52291 - clarify sync_fetch_and_OP for pointers
Authentication-results: sourceware.org; auth=none
References: <56A0221C dot 5060506 at gmail dot com>

On 01/20/2016 05:11 PM, Martin Sebor wrote:

The bug points out that while the __sync_fetch_and_OP intrinsics are
documented to have semantics equivalent to the "x OP= y" compound
assignment expressions, when used with pointer operands they actually
behave as if they operated on integers.  I.e., they are not scaled by
the size of the pointed-to type.

The attached patch brings the documentation of both the __sync_ and
the __atomic_ intrinsics into alignment with their actual effects.

Martin

PS See also c/64843 for some additional background.

gcc-52291.patch


2016-01-20  Martin Sebor<msebor@redhat.com>

	PR c/52291
	* extend.texi (__sync Builtins): Clarify the semantics aof
	__sync_fetch_and_OP built-ins on pointers.
	(__atomic Builtins): Same.

OK
jeff

References:
- [PATCH] #52291 - clarify sync_fetch_and_OP for pointers
  - From: Martin Sebor

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