On Mon, 13 Jun 2016, Kyrill Tkachov wrote:
This patch allows the vectoriser to synthesize multiplications by an
integer constant using the algorithms determined by choose_mult_variant
from expmed.c. choose_mult_variant returns an algorithm structure that
is a linked list of steps describing how to synthesize an integer
multiplication by any constant using shifts, adds, subs, and negation.
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.
Note that we synthesize the multiplications if the target does not
support a vector multiplication in the current vector mode we're
processing. So, for aarch64 this effectively means V2DI (aarch64 has a
vector multiply instruction for narrower inner modes).
I guess I should drop my patch
https://gcc.gnu.org/ml/gcc-patches/2016-06/msg00881.html
This one seems much better.
--
Marc Glisse
