Luke Lau c0f7d51e8a
[VPlan] Simplify ExplicitVectorLength(%AVL) -> %AVL when AVL <= VF (#167647)
[`llvm.experimental.get.vector.length`](https://llvm.org/docs/LangRef.html#id2399)
has the property that if the AVL (%cnt) is less than or equal to VF
(%max_lanes) then the return value is just AVL.

This patch uses SCEV to simplify this in optimizeForVFAndUF, and adds
`ExplicitVectorLength` to
`VPInstruction::opcodeMayReadOrWriteFromMemory` so it gets removed once
dead.
2025-11-13 13:17:01 +00:00
..