In preparation to strip VPUnrollPartAccessor and unroll recipes
directly, strip unnecessary complication in getGEPIndexTy, as the unroll
part will no longer be available in follow-ups (see #168886 for
instance). The patch also helps by doing a mass test update up-front.
Narrowing the GEP index type conditionally does not yield any benefit,
and the change is non-functional in terms of emitted assembly. While at
it, avoid hard-coding address-space 0, and use the pointer operand's
address space to get the GEP index type.
VPVectorPointer for part 0 is just the pointer operand. Simplify it
after unrolling. This removes a large number of redundant GEPs with
index 0.
PR: https://github.com/llvm/llvm-project/pull/149735
Follow-up to dfca6c0d3bf9d1a056 to extend isUnrolled handle any unrolled
VPlan, which means there's a single UF, but it will be > 1 if unrolling
took place.
After unrolling, there may be additional simplifications that can be
applied. One example is removing SCALAR-STEPS for the first part where
only the first lane is demanded.
This removes redundant adds of 0 from a large number of tests (~200),
many which I am still working on updating.
In preparation for removing redundant WideIV steps added in
https://github.com/llvm/llvm-project/pull/119284.
PR: https://github.com/llvm/llvm-project/pull/123655
