https://gcc.gnu.org/bugzilla/show_bug.cgi?id=25111
Jeffrey A. Law <law at redhat dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2016-11-19
CC| |law at redhat dot com
Ever confirmed|0 |1
--- Comment #3 from Jeffrey A. Law <law at redhat dot com> ---
There's a variant for bclr as well. Essentially by using &~ rather than IOR or
XOR. That internally uses a rotate of -2 by the count to generate a mask.
We don't catch the case there A is an argument because it's coming out of
memory and it just gets too complex for the combiner to handle.
So in the end, it's 3 relatively simple patterns. I'm not seeing hits in GCC's
runtime or newlib, but I trust Kazu enough to assume his suggestion could well
have come from a real codebase.
I'll be committing a fix shortly.
