On Wed, May 25, 2011 at 9:43 AM, Andrew Haley <a...@redhat.com> wrote:
> On 05/25/2011 04:32 PM, H.J. Lu wrote:
>> On Wed, May 25, 2011 at 8:27 AM, Richard Guenther
>> <richard.guent...@gmail.com> wrote:
>>> On Wed, May 25, 2011 at 5:20 PM, Michael Matz <m...@suse.de> wrote:
>>>> Hi,
>>>>
>>>> On Wed, 25 May 2011, Richard Guenther wrote:
>>>>
>>>>>>> asm volatile ("" : : : "memory") in fact will work as a full memory
>>>>>>> barrier
>>>>>>
>>>>>> How? You surely need MFENCE or somesuch, unless all you care about is
>>>>>> a compiler barrier. That's what I think needs to be clarified.
>>>>>
>>>>> Well, yes, I'm talking about the compiler memory barrier.
>>>>
>>>> Something that we conventionally call "optimization barrier" :) memory
>>>> barrier has a fixed meaning which we shouldn't use in this case, it's
>>>> confusing.
>>>
>>> Sure ;)
>>>
>>> And to keep the info in a suitable thread what I'd like to improve here
>>> is to make us disambiguate memory loads/stores against asms that
>>> have no memory outputs/inputs.
>>>
>>
>> Please let me know how I should improve the document,
>
> "Compiler memory barrier" seems to be well-understood. I suggest
>
> +Generates the @code{pause} machine instruction with a compiler memory
> barrier.
>
> It's clear enough.
>
> Andrew.
>
I checked in this.
Thanks.
--
H.J.
---
Index: doc/extend.texi
===================================================================
--- doc/extend.texi (revision 174216)
+++ doc/extend.texi (working copy)
@@ -8699,7 +8699,8 @@ The following built-in function is alway
@table @code
@item void __builtin_ia32_pause (void)
-Generates the @code{pause} machine instruction with full memory barrier.
+Generates the @code{pause} machine instruction with a compiler memory
+barrier.
@end table
The following floating point built-in functions are made available in the
Index: ChangeLog
===================================================================
--- ChangeLog (revision 174216)
+++ ChangeLog (working copy)
@@ -1,3 +1,8 @@
+2011-05-25 H.J. Lu <hongjiu...@intel.com>
+
+ * doc/extend.texi (X86 Built-in Functions): Update pause
+ intrinsic.
+
2011-05-25 Bernd Schmidt <ber...@codesourcery.com>
PR bootstrap/49160
