[RISCV] Split zvlsseg searchable table into 4 separate tables. Index by properties rather than intrinsic ID.

Intrinsic ID is a 32-bit value which made each row of the table 4
byte aligned. The remaining fields used 5 bytes. This meant 3 bytes
of padding per row.

This patch breaks the table into 4 separate tables and indexes them
by properties we know about the intrinsic. NF, masked,
strided, ordered, etc. The indexed load/store tables have no
padding in their rows now.

All together this reduces the size of llc binary by ~28K.

I'm considering adding similar tables for isel of non-segment
load/store as well to cut down the size of the isel table and
probably improve our isel performance. Those tables would need to
indexed from intrinsics, IR loads/stores, gathers/scatters, and
RISCVISD opcodes. So having a table that can be indexed without using
intrinsic ID is more flexible.

Reviewed By: HsiangKai

Differential Revision: https://reviews.llvm.org/D96894

GitOrigin-RevId: 8ed3bbbcc35233dce19f77208c2f3d21c3f68902
3 files changed