[all-commits] [llvm/llvm-project] af935c: [CodeLayout] Fix X1_Y_X2 and Y_X2_X1 testing for j...

[Fangrui Song via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: af935cf0ee8a26dcf0860ed0c72d74b4a1cb1314
      https://github.com/llvm/llvm-project/commit/af935cf0ee8a26dcf0860ed0c72d74b4a1cb1314
  Author: Fangrui Song <i at maskray.me>
  Date:   2023-09-18 (Mon, 18 Sep 2023)

  Changed paths:
    M llvm/lib/Transforms/Utils/CodeLayout.cpp
    M llvm/test/CodeGen/X86/code_placement_ext_tsp_large.ll

  Log Message:
  -----------
  [CodeLayout] Fix X1_Y_X2 and Y_X2_X1 testing for jumps from Y (#66592)

The CHECK2 test in code_placement_ext_tsp_large.ll now has the same
result as
the CHECK test: when chain(0,2,3,4,1) is merged with chain(8), the
result is now
chain(0,2,3,4,8,1).

Ideally we should have test coverage for
-ext-tsp-chain-split-threshold=1, but
it seems challenging to craft one. Perhaps the default value of
-ext-tsp-chain-split-threshold can be decreased as the
-ext-tsp-enable-chain-split-along-jumps heuristic is now more powerful.