[AArch64] Improve code generation of constant vectors
Use the whole gammut of constant immediates available to set up a vector.
Instead of using, for example, `mov w0, #0xffff; dup v0.4s, w0`, which
transfers between register files, use the more efficient `movi v0.4s, #-1`
instead. Not limited to just a few values, but any immediate value that can
be encoded by all the variants of `FMOV`, `MOVI`, `MVNI`, thus eliminating
the need to there be patterns to optimize special cases.
Differential revision: https://reviews.llvm.org/D42133
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@326718 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed