[PATCH] compiler-gcc*.h: remove inaccurate comment about 'asm goto' miscompiles

[PATCH] compiler-gcc*.h: remove inaccurate comment about 'asm goto' miscompiles

[Steven Noonan]

The bug referenced by the comment in this commit was not completely fixed in
GCC 4.8.2, as I mentioned in a thread back in February[1]. The conclusion at
that time was to make the quirk unconditional until the bug could be found and
fixed in GCC. Unfortunately, when I submitted the patch (commit a9f18034)
I left a comment in that claimed the bug was fixed in GCC 4.8.2+.  This comment
is inaccurate, and should be removed.

[1] https://lkml.org/lkml/2014/2/12/797
Signed-off-by: Steven Noonan <steven@uplinklabs.net>
Cc: Ingo Molnar <mingo@kernel.org>
---
 include/linux/compiler-gcc4.h | 1 -
 include/linux/compiler-gcc5.h | 1 -
 2 files changed, 2 deletions(-)

diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h
index 2507fd2..d1a5582 100644
--- a/include/linux/compiler-gcc4.h
+++ b/include/linux/compiler-gcc4.h
@@ -71,7 +71,6 @@
  *   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
  *
  * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
- * Fixed in GCC 4.8.2 and later versions.
  *
  * (asm goto is automatically volatile - the naming reflects this.)
  */
diff --git a/include/linux/compiler-gcc5.h b/include/linux/compiler-gcc5.h
index cdd1cc2..c8c5659 100644
--- a/include/linux/compiler-gcc5.h
+++ b/include/linux/compiler-gcc5.h
@@ -53,7 +53,6 @@
  *   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
  *
  * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
- * Fixed in GCC 4.8.2 and later versions.
  *
  * (asm goto is automatically volatile - the naming reflects this.)
  */
-- 
2.1.2

[tip:core/urgent] compiler/gcc4+: Remove inaccurate comment about 'asm goto' miscompiles

[tip-bot for Steven Noonan]

Commit-ID:  5631b8fba640a4ab2f8a954f63a603fa34eda96b
Gitweb:     http://git.kernel.org/tip/5631b8fba640a4ab2f8a954f63a603fa34eda96b
Author:     Steven Noonan <steven@uplinklabs.net>
AuthorDate: Sat, 25 Oct 2014 15:09:42 -0700
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 28 Oct 2014 11:03:40 +0100

compiler/gcc4+: Remove inaccurate comment about 'asm goto' miscompiles

The bug referenced by the comment in this commit was not
completely fixed in GCC 4.8.2, as I mentioned in a thread back
in February:

   https://lkml.org/lkml/2014/2/12/797

The conclusion at that time was to make the quirk unconditional
until the bug could be found and fixed in GCC. Unfortunately,
when I submitted the patch (commit a9f18034) I left a comment
in that claimed the bug was fixed in GCC 4.8.2+.

This comment is inaccurate, and should be removed.

Signed-off-by: Steven Noonan <steven@uplinklabs.net>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1414274982-14040-1-git-send-email-steven@uplinklabs.net
Cc: Ingo Molnar <mingo@kernel.org>
---
 include/linux/compiler-gcc4.h | 1 -
 include/linux/compiler-gcc5.h | 1 -
 2 files changed, 2 deletions(-)

diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h
index 2507fd2..d1a5582 100644
--- a/include/linux/compiler-gcc4.h
+++ b/include/linux/compiler-gcc4.h
@@ -71,7 +71,6 @@
  *   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
  *
  * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
- * Fixed in GCC 4.8.2 and later versions.
  *
  * (asm goto is automatically volatile - the naming reflects this.)
  */
diff --git a/include/linux/compiler-gcc5.h b/include/linux/compiler-gcc5.h
index cdd1cc2..c8c5659 100644
--- a/include/linux/compiler-gcc5.h
+++ b/include/linux/compiler-gcc5.h
@@ -53,7 +53,6 @@
  *   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
  *
  * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
- * Fixed in GCC 4.8.2 and later versions.
  *
  * (asm goto is automatically volatile - the naming reflects this.)
  */

Re: [PATCH] compiler-gcc*.h: remove inaccurate comment about 'asm goto' miscompiles

[Vlastimil Babka]

On 10/26/2014 12:09 AM, Steven Noonan wrote:
> The bug referenced by the comment in this commit was not completely fixed in
> GCC 4.8.2, as I mentioned in a thread back in February[1]. The conclusion at
> that time was to make the quirk unconditional until the bug could be found and
> fixed in GCC. Unfortunately, when I submitted the patch (commit a9f18034)
> I left a comment in that claimed the bug was fixed in GCC 4.8.2+.  This comment
> is inaccurate, and should be removed.

I believe the original gcc bug was indeed fixed, but there's another bug [1] not
yet fixed, see also [2]. So maybe the new bug number should be added to the
comments?

Vlastimil

[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61772
[2] https://lkml.org/lkml/2014/7/10/398

> [1] https://lkml.org/lkml/2014/2/12/797
> Signed-off-by: Steven Noonan <steven@uplinklabs.net>
> Cc: Ingo Molnar <mingo@kernel.org>
> ---
>  include/linux/compiler-gcc4.h | 1 -
>  include/linux/compiler-gcc5.h | 1 -
>  2 files changed, 2 deletions(-)
> 
> diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h
> index 2507fd2..d1a5582 100644
> --- a/include/linux/compiler-gcc4.h
> +++ b/include/linux/compiler-gcc4.h
> @@ -71,7 +71,6 @@
>   *   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
>   *
>   * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
> - * Fixed in GCC 4.8.2 and later versions.
>   *
>   * (asm goto is automatically volatile - the naming reflects this.)
>   */
> diff --git a/include/linux/compiler-gcc5.h b/include/linux/compiler-gcc5.h
> index cdd1cc2..c8c5659 100644
> --- a/include/linux/compiler-gcc5.h
> +++ b/include/linux/compiler-gcc5.h
> @@ -53,7 +53,6 @@
>   *   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
>   *
>   * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
> - * Fixed in GCC 4.8.2 and later versions.
>   *
>   * (asm goto is automatically volatile - the naming reflects this.)
>   */
>