Re: Possible wrong-way example in gcc4-4-2 documentation of __builtin_expect
On 21 December 2011 02:00, Jim Avera wrote:
Ok, here is a patch which improves the example:
--- gcc/doc/extend.texi.ORIG 2011-12-20 17:35:32.236578828 -0800
+++ gcc/doc/extend.texi 2011-12-20 17:37:10.460583316 -0800
@@ -7932,7 +7932,7 @@
@smallexample
if (__builtin_expect (ptr != NULL, 1))
- error ();
+ ptr-do_something();
@end smallexample
@noindent
In order to follow the GCC coding style (a space between the function
name and opening parenthesis) and to match the first example for
__builtin_expect, I propose this patch instead:
Index: extend.texi
===
--- extend.texi (revision 182452)
+++ extend.texi (working copy)
@@ -7932,7 +7932,7 @@ expressions for @var{exp}, you should us
@smallexample
if (__builtin_expect (ptr != NULL, 1))
- error ();
+ ptr-foo ();
@end smallexample
@noindent
I've CC'd the gcc-patches list, which is where patches should be sent
for review, and included a ChangeLog entry:
2011-12-21 Jonathan Wakely jwakely@gmail.com
Jim Avera james_av...@yahoo.com
* doc/extend.texi (__builtin_expect): Improve example.
Can I get approval to check this in to trunk?
From: Jonathan Wakely jwakely@gmail.com
To: Segher Boessenkool seg...@kernel.crashing.org
Cc: james_av...@yahoo.com; gcc@gcc.gnu.org
Sent: Tuesday, December 20, 2011 5:22 AM
Subject: Re: Possible wrong-way example in gcc4-4-2 documentation of
__builtin_expect
On 20 December 2011 12:49, Segher Boessenkool wrote:
The point of the example is that you cannot write
if (__builtin_expect (ptr, 1))
error ();
so the != NULL is important here. But you are right that
error () is a bit unexpected; care to send a patch that changes
it to e.g. do_something ()?
or even ptr-do_something() since that would depend on the value of ptr
Re: Possible wrong-way example in gcc4-4-2 documentation of __builtin_expect
On 21 December 2011 18:03, Jonathan Wakely wrote:
On 21 December 2011 02:00, Jim Avera wrote:
Ok, here is a patch which improves the example:
--- gcc/doc/extend.texi.ORIG 2011-12-20 17:35:32.236578828 -0800
+++ gcc/doc/extend.texi 2011-12-20 17:37:10.460583316 -0800
@@ -7932,7 +7932,7 @@
@smallexample
if (__builtin_expect (ptr != NULL, 1))
- error ();
+ ptr-do_something();
@end smallexample
@noindent
In order to follow the GCC coding style (a space between the function
name and opening parenthesis) and to match the first example for
__builtin_expect, I propose this patch instead:
Index: extend.texi
===
--- extend.texi (revision 182452)
+++ extend.texi (working copy)
@@ -7932,7 +7932,7 @@ expressions for @var{exp}, you should us
@smallexample
if (__builtin_expect (ptr != NULL, 1))
- error ();
+ ptr-foo ();
@end smallexample
@noindent
Then again, maybe foo (*ptr) would be even better, so it looks more
like C not C++ code.
I've CC'd the gcc-patches list, which is where patches should be sent
for review, and included a ChangeLog entry:
2011-12-21 Jonathan Wakely jwakely@gmail.com
Jim Avera james_av...@yahoo.com
* doc/extend.texi (__builtin_expect): Improve example.
Can I get approval to check this in to trunk?
From: Jonathan Wakely jwakely@gmail.com
To: Segher Boessenkool seg...@kernel.crashing.org
Cc: james_av...@yahoo.com; gcc@gcc.gnu.org
Sent: Tuesday, December 20, 2011 5:22 AM
Subject: Re: Possible wrong-way example in gcc4-4-2 documentation of
__builtin_expect
On 20 December 2011 12:49, Segher Boessenkool wrote:
The point of the example is that you cannot write
if (__builtin_expect (ptr, 1))
error ();
so the != NULL is important here. But you are right that
error () is a bit unexpected; care to send a patch that changes
it to e.g. do_something ()?
or even ptr-do_something() since that would depend on the value of ptr
Re: Possible wrong-way example in gcc4-4-2 documentation of __builtin_expect
Jonathan Wakely jwakely@gmail.com writes:
In order to follow the GCC coding style (a space between the function
name and opening parenthesis) and to match the first example for
__builtin_expect, I propose this patch instead:
Index: extend.texi
===
--- extend.texi (revision 182452)
+++ extend.texi (working copy)
@@ -7932,7 +7932,7 @@ expressions for @var{exp}, you should us
@smallexample
if (__builtin_expect (ptr != NULL, 1))
- error ();
+ ptr-foo ();
@end smallexample
@noindent
I've CC'd the gcc-patches list, which is where patches should be sent
for review, and included a ChangeLog entry:
2011-12-21 Jonathan Wakely jwakely@gmail.com
Jim Avera james_av...@yahoo.com
* doc/extend.texi (__builtin_expect): Improve example.
Can I get approval to check this in to trunk?
This is fine, with or without your proposed change.
Thanks.
Ian
Re: Possible wrong-way example in gcc4-4-2 documentation of __builtin_expect
On 21 December 2011 02:00, Jim Avera wrote:
Ok, here is a patch which improves the example:
--- gcc/doc/extend.texi.ORIG 2011-12-20 17:35:32.236578828 -0800
+++ gcc/doc/extend.texi 2011-12-20 17:37:10.460583316 -0800
@@ -7932,7 +7932,7 @@
@smallexample
if (__builtin_expect (ptr != NULL, 1))
- error ();
+ ptr-do_something();
@end smallexample
@noindent
In order to follow the GCC coding style (a space between the function
name and opening parenthesis) and to match the first example for
__builtin_expect, I propose this patch instead:
Index: extend.texi
===
--- extend.texi (revision 182452)
+++ extend.texi (working copy)
@@ -7932,7 +7932,7 @@ expressions for @var{exp}, you should us
@smallexample
if (__builtin_expect (ptr != NULL, 1))
- error ();
+ ptr-foo ();
@end smallexample
@noindent
I've CC'd the gcc-patches list, which is where patches should be sent
for review, and included a ChangeLog entry:
2011-12-21 Jonathan Wakely jwakely@gmail.com
Jim Avera james_av...@yahoo.com
* doc/extend.texi (__builtin_expect): Improve example.
Can I get approval to check this in to trunk?
From: Jonathan Wakely jwakely@gmail.com
To: Segher Boessenkool seg...@kernel.crashing.org
Cc: james_av...@yahoo.com; g...@gcc.gnu.org
Sent: Tuesday, December 20, 2011 5:22 AM
Subject: Re: Possible wrong-way example in gcc4-4-2 documentation of
__builtin_expect
On 20 December 2011 12:49, Segher Boessenkool wrote:
The point of the example is that you cannot write
if (__builtin_expect (ptr, 1))
error ();
so the != NULL is important here. But you are right that
error () is a bit unexpected; care to send a patch that changes
it to e.g. do_something ()?
or even ptr-do_something() since that would depend on the value of ptr
Re: Possible wrong-way example in gcc4-4-2 documentation of __builtin_expect
On 21 December 2011 18:03, Jonathan Wakely wrote:
On 21 December 2011 02:00, Jim Avera wrote:
Ok, here is a patch which improves the example:
--- gcc/doc/extend.texi.ORIG 2011-12-20 17:35:32.236578828 -0800
+++ gcc/doc/extend.texi 2011-12-20 17:37:10.460583316 -0800
@@ -7932,7 +7932,7 @@
@smallexample
if (__builtin_expect (ptr != NULL, 1))
- error ();
+ ptr-do_something();
@end smallexample
@noindent
In order to follow the GCC coding style (a space between the function
name and opening parenthesis) and to match the first example for
__builtin_expect, I propose this patch instead:
Index: extend.texi
===
--- extend.texi (revision 182452)
+++ extend.texi (working copy)
@@ -7932,7 +7932,7 @@ expressions for @var{exp}, you should us
@smallexample
if (__builtin_expect (ptr != NULL, 1))
- error ();
+ ptr-foo ();
@end smallexample
@noindent
Then again, maybe foo (*ptr) would be even better, so it looks more
like C not C++ code.
I've CC'd the gcc-patches list, which is where patches should be sent
for review, and included a ChangeLog entry:
2011-12-21 Jonathan Wakely jwakely@gmail.com
Jim Avera james_av...@yahoo.com
* doc/extend.texi (__builtin_expect): Improve example.
Can I get approval to check this in to trunk?
From: Jonathan Wakely jwakely@gmail.com
To: Segher Boessenkool seg...@kernel.crashing.org
Cc: james_av...@yahoo.com; g...@gcc.gnu.org
Sent: Tuesday, December 20, 2011 5:22 AM
Subject: Re: Possible wrong-way example in gcc4-4-2 documentation of
__builtin_expect
On 20 December 2011 12:49, Segher Boessenkool wrote:
The point of the example is that you cannot write
if (__builtin_expect (ptr, 1))
error ();
so the != NULL is important here. But you are right that
error () is a bit unexpected; care to send a patch that changes
it to e.g. do_something ()?
or even ptr-do_something() since that would depend on the value of ptr
Re: Possible wrong-way example in gcc4-4-2 documentation of __builtin_expect
Jonathan Wakely jwakely@gmail.com writes:
In order to follow the GCC coding style (a space between the function
name and opening parenthesis) and to match the first example for
__builtin_expect, I propose this patch instead:
Index: extend.texi
===
--- extend.texi (revision 182452)
+++ extend.texi (working copy)
@@ -7932,7 +7932,7 @@ expressions for @var{exp}, you should us
@smallexample
if (__builtin_expect (ptr != NULL, 1))
- error ();
+ ptr-foo ();
@end smallexample
@noindent
I've CC'd the gcc-patches list, which is where patches should be sent
for review, and included a ChangeLog entry:
2011-12-21 Jonathan Wakely jwakely@gmail.com
Jim Avera james_av...@yahoo.com
* doc/extend.texi (__builtin_expect): Improve example.
Can I get approval to check this in to trunk?
This is fine, with or without your proposed change.
Thanks.
Ian
Re: Possible wrong-way example in gcc4-4-2 documentation of __builtin_expect
The online docs at http://gcc.gnu.org/onlinedocs/gcc-4.4.2/gcc/Other-Builtins.html has a confusing (to me) example of __builtin_expect. Could someone take a look at this? start quote from above-referenced page Since you are limited to integral expressions for exp, you should use constructions such as if (__builtin_expect (ptr != NULL, 1)) error (); end quote This seems backwards.The return value of __builtin_expect is the first argument, namely (ptr != NULL), which presumably is true in the NON-error case. The following example might be more helpful: if (__builtin_expect (ptr == NULL, 0)) error (); Apologies if I'm not reading this correctly. The point of the example is that you cannot write if (__builtin_expect (ptr, 1)) error (); so the != NULL is important here. But you are right that error () is a bit unexpected; care to send a patch that changes it to e.g. do_something ()? Segher
Re: Possible wrong-way example in gcc4-4-2 documentation of __builtin_expect
On 20 December 2011 12:49, Segher Boessenkool wrote: The point of the example is that you cannot write if (__builtin_expect (ptr, 1)) error (); so the != NULL is important here. But you are right that error () is a bit unexpected; care to send a patch that changes it to e.g. do_something ()? or even ptr-do_something() since that would depend on the value of ptr
Re: Possible wrong-way example in gcc4-4-2 documentation of __builtin_expect
Ok, here is a patch which improves the example: --- gcc/doc/extend.texi.ORIG 2011-12-20 17:35:32.236578828 -0800 +++ gcc/doc/extend.texi 2011-12-20 17:37:10.460583316 -0800 @@ -7932,7 +7932,7 @@ @smallexample if (__builtin_expect (ptr != NULL, 1)) - error (); + ptr-do_something(); @end smallexample @noindent From: Jonathan Wakely jwakely@gmail.com To: Segher Boessenkool seg...@kernel.crashing.org Cc: james_av...@yahoo.com; gcc@gcc.gnu.org Sent: Tuesday, December 20, 2011 5:22 AM Subject: Re: Possible wrong-way example in gcc4-4-2 documentation of __builtin_expect On 20 December 2011 12:49, Segher Boessenkool wrote: The point of the example is that you cannot write if (__builtin_expect (ptr, 1)) error (); so the != NULL is important here. But you are right that error () is a bit unexpected; care to send a patch that changes it to e.g. do_something ()? or even ptr-do_something() since that would depend on the value of ptr
