Ping? (link to original post:
https://gcc.gnu.org/ml/gcc-patches/2016-03/msg00743.html )
This patch adds a sample for a new-to-v6 feature. Is this not the right
time for doc improvements?
I considered adding some assembler output. Something like:
------------------------
Before this feature, you had to write code like this:
asm("bt $0, %1 ; setc %0" : "=q" (a) : "r" (value) : "cc");
if (a)
This would generate code like this:
bt $0, %ebx
setc %al <--------- Convert flags to byte
testb %al, %al <------ Convert byte back to flags
jne .L5
Using @cc, this code
asm("bt $0, %1" : "=@ccc" (a) : "r" (value) );
if (a)
produces this output:
bt $0, %ebx
jc .L5 <--------- Use the flags directly
----------------
While this helps show the benefit of the feature, it just seemed like
too much detail. Showing people the c code and reminding them to enable
optimizations (what the current patch does) seems like it should be
sufficient.
dw
On 3/12/2016 8:00 PM, David Wohlferd wrote:
The docs for the new(-ish) @cc constraint need an example. Attached.
ChangeLog:
2016-03-12 David Wohlferd <d...@limegreensocks.com>
* doc/extend.texi: Add sample for @cc constraint
Note that while I have a release on file with FSF, I don't have write
access to SVN.
dw
