[PATCH] D109369: [AArch64][SVE] Add missing patterns for unpredicated subr intrinsics

[Bradley Smith via Phabricator via llvm-commits]

bsmith added a comment.

In D109369#2987058 <https://reviews.llvm.org/D109369#2987058>, @paulwalker-arm wrote:

> My first thought is if you lowered "unpredicated" `int_aarch64_sve_subr` much like we do for `int_aarch64_sve_sub`, would we then get the isel improvements for free?

I did consider this, however we'd have to add a new SUBR node for it, and given it won't be used elsewhere, unlike lowering the add, it didn't seem worth it. Additionally we wouldn't quite get the isel improvements for free as unpredicted subr is expressed in terms of sub, not subr, hence we'd still have to add extra patterns, they just wouldn't need to care about predicates.

That said, now that I think about it again, perhaps we could lower int_aarch64_sve_subr to a normal sub with reversed operands, which then I think would give us the isel for free, unless this is what you meant?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D109369/new/

https://reviews.llvm.org/D109369