On 07/30/2015 04:19 PM, Evgeny Stupachenko wrote:
Hi All,
The patch enables new attribute 'ctarget',
The attribute force compiler to create clones of a function with the attribute.
For example:
__attribute__((ctarget("avx","arch=slm","arch=core-avx2","default")))
So presumably we're allowing both changing the ISA and the tuning
options? In fact, it looks like we're able to change any -m option, right?
What about something like -mregparm? I think the docs need to disallow
clones with different ABI requirements.
Currently default ctarget means that foo() will be optimized with
current compiler options and target.
The other option is to switch target to target specific minimum (like
target x86-64). Is it better?
I could make an argument for either. Do we have anything to guide us
from other compilers such as ICC that may have a similar capability?
What do you think about attribute name? 'ctarget' is short but not
informative. Other variants are 'target_clones', 'targets'...
target_clones seems good.
For multiple_target.c: Can you please trim down the #include set. I
can't believe you need all that stuff. If you really need backend
stuff (tm.h), then use "backend.h" instead.
It generally looks reasonable, but Jan knows the IPA code much better
than I do and I'd like him to chime in. You might also ask Ilya to
review the cloning and rules around clones since he head to deal with a
lot of that stuff in his MPX work.
jeff
