[Bug middle-end/29274] [4.3/4.4/4.5 Regression] not using mulsidi3

[rguenth at gcc dot gnu dot org]

------- Comment #9 from rguenth at gcc dot gnu dot org  2009-08-26 18:35 -------
Note that even for

  (long long)i * (long long)j * (long long)i

we can only use one mulsidi3, so promoting parts of the multiplications to
additions should be still beneficial.

I suppose we should detect widening multiply on the tree level before
re-association where it is beneficial (if the target doesn't have a native
wide multiplication).


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29274