[Bug target/43902] suboptimal MIPS widening multiply accumulate

["bernds at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #9 from bernds at gcc dot gnu dot org  2010-06-09 20:20 -------
Created an attachment (id=20880)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20880&action=view)
A new version of Jim's patch

Here's what I've done with it so far.  I've changed the new tree code to be a
proper gimple operation, which meant extending all sorts of gimple code to
handle ternary operations.  tree-ssa-math-opts runs late enough that I don't
think we need to handle them in most passes, so I've turned some existing
functions into wrappers that continue to present a two-operand interface.

The other thing I've done is to restructure the pass a little to avoid the
second loop over all the insns.

I've changed the ARM backend to take advantage of it.

Regression tests on ARM look fine (although I've had to change one of the
testcases which didn't expect widen-macc to be generated).

What do you think?  Please let me know what your MIPS tests turned up.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43902