The following happens to improve compile-time of the PR103641
testcase on aarch64 significantly. I did not investigate the
effect on the generated code but at least in theory
choose_mult_variant should do a better job when we tell it
the actual mode we are going to use for the operations it
synthesizes.
2022-02-04 Richard Biener <rguenther@suse.de>
PR tree-optimization/103641
* tree-vect-patterns.cc (vect_synth_mult_by_constant):
Pass the vector mode to choose_mult_variant.