On Mon, 13 Jun 2016, Kyrill Tkachov wrote:
The new function vect_synth_mult_by_constant that does all the hard work is very similar in structure to expand_mult_const from expmed.c but it operates on gimple SSA rather than RTL.
I think in some cases this transformation creates undefined overflow from well-defined code. While this is fine in RTL, I would expect to need a cast to unsigned_type_for in gimple for some of the algorithms.
(not completely sure, just something to look at) -- Marc Glisse
