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From: "dje at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/51766] New: [4.7 regression] sync_fetch_and_xxx atomicity
Date: Thu, 05 Jan 2012 15:01:00 -0000 [thread overview]
Message-ID: <bug-51766-4@http.gcc.gnu.org/bugzilla/> (raw)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51766
Bug #: 51766
Summary: [4.7 regression] sync_fetch_and_xxx atomicity
Classification: Unclassified
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: dje@gcc.gnu.org
During the C++11 memory model conversion, expand_builtin_sync_operation was
updated. __sync_fetch_and_xxx and __sync_xxx_and_fetch now invoke
expand_atomic_fetch_op with MEMMODEL_SEQUENTIAL_CST.
return expand_atomic_fetch_op (target, mem, val, code, MEMMODEL_SEQ_CST,
after);
This has changed the memory model semantics of the builtins and causes the
rs6000/POWER architecture to emit a heavy-weight "sync" instruction instead of
a light-weight "lwsync" instruction, which is a regression.
next reply other threads:[~2012-01-05 15:01 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-05 15:01 dje at gcc dot gnu.org [this message]
2012-01-05 15:02 ` [Bug middle-end/51766] " dje at gcc dot gnu.org
2012-01-09 15:40 ` rguenth at gcc dot gnu.org
2012-01-09 15:45 ` redi at gcc dot gnu.org
2012-01-09 16:51 ` dje at gcc dot gnu.org
2012-01-10 9:43 ` rguenth at gcc dot gnu.org
2012-01-10 14:40 ` dje at gcc dot gnu.org
2012-01-10 14:49 ` rguenth at gcc dot gnu.org
2012-01-10 15:31 ` redi at gcc dot gnu.org
2012-01-10 18:09 ` dje at gcc dot gnu.org
2012-01-10 18:20 ` redi at gcc dot gnu.org
2012-01-10 18:24 ` redi at gcc dot gnu.org
2012-01-10 18:34 ` dje at gcc dot gnu.org
2012-01-10 18:47 ` jakub at gcc dot gnu.org
2012-01-10 19:14 ` amacleod at redhat dot com
2012-01-10 20:26 ` dje at gcc dot gnu.org
2012-01-12 20:41 ` dje at gcc dot gnu.org
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