[all-commits] [llvm/llvm-project] 3d092e: Add a new memory allocation rewrite pass.

[Eric Schweitz via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 3d092e31c1f5fab9b427994970616bc5dde3b3be
      https://github.com/llvm/llvm-project/commit/3d092e31c1f5fab9b427994970616bc5dde3b3be
  Author: Eric Schweitz <eschweitz at nvidia.com>
  Date:   2021-12-15 (Wed, 15 Dec 2021)

  Changed paths:
    M flang/include/flang/Optimizer/Transforms/Passes.h
    M flang/include/flang/Optimizer/Transforms/Passes.td
    M flang/lib/Optimizer/Transforms/CMakeLists.txt
    A flang/lib/Optimizer/Transforms/MemoryAllocation.cpp
    A flang/test/Fir/memory-allocation-opt.fir

  Log Message:
  -----------
  Add a new memory allocation rewrite pass.

This pass can reclassify memory allocations (fir.alloca, fir.allocmem)
based on heuristics and settings. The intention is to allow better
performance and workarounds for conditions such as environments with
limited stack space.

Currently, implements two conversions from stack to heap allocation.
  1. If a stack allocation is an array larger than some threshold value
     make it a heap allocation.
  2. If a stack allocation is an array with a runtime evaluated size make
     it a heap allocation.

Add a lit test for both suboptions.

Reviewed By: PeteSteinfeld, vdonaldson

Differential Revision: https://reviews.llvm.org/D115763