hanbeom a2c6b34193
[WebAssembly][FastISel] Fold i64 extension chains into widened loads (#187934)
FastISel can already fold some sign- and zero-extending loads, but a
number of i64 extension patterns still leave redundant instructions
behind.

This patch series extends load folding to recognize several such cases,
including:
- promoted sign-extension chains
- copy + i64.extend_i32_{u,s} chains
- AND-based zero-extension chains
- shift-based sign-extension chains

When these patterns originate from narrow integer loads, fold them
directly into widened i64 loads instead of materializing intermediate
i32 loads followed by redundant i64 extends.

Fixes #179672
2026-03-24 12:56:06 +09:00
..