[DAGCombine] narrowInsertExtractVectorBinOp - add CONCAT_VECTORS support
We already split extract_subvector(binop(insert_subvector(v,x),insert_subvector(w,y))) -> binop(x,y).
This patch adds support for extract_subvector(binop(concat_vectors(),concat_vectors())) cases as well.
In particular this means we don't have to wait for X86 lowering to convert concat_vectors to insert_subvector chains, which helps avoid some cases where demandedelts/combine calls occur too late to split large vector ops.
The fast-isel-store.ll load folding regression is annoying but I don't think is that critical.
Differential Revision: https://reviews.llvm.org/D63653
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@365785
91177308-0d34-0410-b5e6-
96231b3b80d8
projects / llvm / commit