[Bug target/65871] bzhi builtin/intrinsic wrongly assumes bzhi instruction doesn't set the ZF flag

jamrial at gmail dot com gcc-bugzilla@gcc.gnu.org
Sat Apr 25 05:46:00 GMT 2015


https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65871

--- Comment #1 from James Almer <jamrial at gmail dot com> ---
The same apparently happens with bextr, blsi, blsr, and most (if not all) of
AMD's tbm instructions. They set the ZF flag but gcc still generates a test
instruction.

http://www.felixcloutier.com/x86/BEXTR.html
http://www.felixcloutier.com/x86/BLSI.html
http://www.felixcloutier.com/x86/BLSR.html
http://support.amd.com/TechDocs/24594.pdf



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