[all-commits] [llvm/llvm-project] e3abe9: [MachinePipeliner] Improve loop carried dependence...

[Yuta Mukai via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: e3abe940d8fc356bf46a6b71da44df0f4652df1c
      https://github.com/llvm/llvm-project/commit/e3abe940d8fc356bf46a6b71da44df0f4652df1c
  Author: Yuta Mukai <mukai.yuta at fujitsu.com>
  Date:   2025-02-05 (Wed, 05 Feb 2025)

  Changed paths:
    M llvm/include/llvm/CodeGen/MachinePipeliner.h
    M llvm/lib/CodeGen/MachinePipeliner.cpp
    M llvm/test/CodeGen/Hexagon/swp-carried-dep1.mir
    M llvm/test/CodeGen/Hexagon/swp-carried-dep2.mir
    M llvm/test/CodeGen/Hexagon/swp-carried-dep3.mir
    A llvm/test/CodeGen/Hexagon/swp-carried-dep4.mir
    A llvm/test/CodeGen/Hexagon/swp-carried-dep5.mir
    M llvm/test/CodeGen/Hexagon/swp-epilog-phi8.ll

  Log Message:
  -----------
  [MachinePipeliner] Improve loop carried dependence analysis (#94185)

The previous implementation had false positive/negative cases in the
analysis of the loop carried dependency.

A missed dependency case is caused by incorrect analysis of address
increments. This is fixed by strict analysis of recursive definitions.
See added test swp-carried-dep4.mir.

Excessive dependency detection is fixed by improving the formula
for determining the overlap of address ranges to be accessed. See added test
swp-carried-dep5.mir.



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