SVE Enhancements to LLVM
========================

This repository is a clone of the public LLVM repository (http://llvm.org), plus
a single patch which provides support for the ARMv8-A Scalable Vector Extension
(SVE).

ARM is providing this repository to:
* Aid discussions about IR changes to support vectorizing loops in a scalable
  manner
* Allow partners to progress with implementation

This patch is not intended for inclusion directly into upstream LLVM. There is
a separate upstreaming effort, documented in this RFC:
http://lists.llvm.org/pipermail/llvm-dev/2018-July/124396.html

ARM provides no assurances regarding maintenance or support for this repository.
Pull requests will not be accepted.  ARM intends to remove it once upstream
LLVM has sufficiently advanced support for SVE.

This patch includes (but is not limited to):
* Support for scalable vector types in the IR and SelectionDAG
* New IR constants and corresponding ISD opcodes:
  * vcount
  * stepvector
* A new intrinsic to partition predicate vectors and a corresponding opcode:
  * propff
* A forked LoopVectorize pass (SVELoopVectorize) which uses these new IR
  constructs to vectorize loops in a vector-length-agnostic manner with loop
  control flow based on predication
* Changes in multiple passes to support the new constructs and scalable types
* Changes in multiple passes to increase opportunities for vectorization
* New AArch64 target passes to recognize common patterns and replace with
  intrinsics
* Tablegen modifications to support the new MVTs and provide better operand
  matching
* Instruction/register info td files and lowering code for SVE
* A provisional implementation of an SVE procedure call standard, may be changed
  in future

Contributors:
Alban Bridonneau
Amara Emerson
Andra-Maria Ilies
Assad Hashmi
Cullen Rhodes
David Sherwood
Florian Hahn
Francesco Petrogalli
Graham Hunter
Joshua Warburton
Kerry McLaughlin
Kiran Chandramohan
Maciej Gabka
Paul Walker
Prakhar Bahuguna
Richard Sandiford
Sander De Smalen
Will Lovett