https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70923
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |missed-optimization
Status|UNCONFIRMED |NEW
Last reconfirmed| |2016-05-03
Ever confirmed|0 |1
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
I think this is the x + x -> 2 * x canonicalization we now perform. That's bad
when the target cannot vectorize integer multiplication.
We have vect_recog_mult_pattern that should have triggered here but that
only tries replacement with LSHIFT_EXPR rather than also a simple plus
for 2 * x.
Likely caused by
2016-04-26 Marc Glisse <marc.gli...@inria.fr>
* genmatch.c (write_predicate): Add ATTRIBUTE_UNUSED.
* fold-const.c (fold_binary_loc): Remove 2 transformations
superseded by match.pd.
* match.pd (x+x -> x*2): Generalize to integers.
