[all-commits] [llvm/llvm-project] d7dd12: [LV] Disable Scalable VFs when tail folding is ena...

[sdesmalen-arm via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: d7dd12aee399a19e890143604b6993f02232ca24
      https://github.com/llvm/llvm-project/commit/d7dd12aee399a19e890143604b6993f02232ca24
  Author: Sander de Smalen <sander.desmalen at arm.com>
  Date:   2021-07-27 (Tue, 27 Jul 2021)

  Changed paths:
    M llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
    A llvm/test/Transforms/LoopVectorize/AArch64/sve-tail-folding.ll

  Log Message:
  -----------
  [LV] Disable Scalable VFs when tail folding is enabled b/c of low tripcount.

The loop vectorizer may decide to use tail folding when the trip-count
is low. When that happens, scalable VFs are no longer a candidate,
since tail folding/predication is not yet supported for scalable vectors.

This can be re-enabled in a future patch.

Reviewed By: kmclaughlin

Differential Revision: https://reviews.llvm.org/D106657