CC0 to CCmode conversion

James E Wilson wilson@specifixinc.com
Tue Mar 22 22:16:00 GMT 2005


Denis Chertykov wrote:
> I think that sequence of compare + cond-jump will exists in any
> compiler pass.

Combine can optimize away compares, if you have other instructions that 
set the condition code register to useful values.  This optimization 
will only work correctly if instructions that set or clobber the cc are 
properly marked.

If no instructions are marked as setting the cc (other than compares), 
then this will probably work, but you won't get any optimization from 
combine, and may get worse code than before.
-- 
Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com



More information about the Gcc mailing list