)]}'
{
  "commit": "85318bae285e9103acbc75ad3bdf78db1ce56f21",
  "tree": "82c852961990914fbfab88e27e1866694cdb8cd6",
  "parents": [
    "28ffa7f6a4d609e097a4861090f42c35459e9303"
  ],
  "author": {
    "name": "Jonas Paulsson",
    "email": "paulson1@linux.ibm.com",
    "time": "Thu Mar 13 08:50:54 2025 -0600"
  },
  "committer": {
    "name": "GitHub",
    "email": "noreply@github.com",
    "time": "Thu Mar 13 15:50:54 2025 +0100"
  },
  "message": "[MachineLateInstrsCleanup] Handle multiple kills for a preceding definition. (#119132)\n\nWhen removing a redundant definition in order to reuse an earlier\nidentical one it is necessary to remove any earlier kill flag as well.\n\nPreviously, the assumption has been that any register that kills the\ndefined Reg is enough to handle for this purpose, but this is actually\nnot quite enough. A kill of a super-register does not necessarily imply\nthat all of its subregs (including Reg) is defined at that point: a\npartial definition of a register is legal. This means Reg may have been\nkilled earlier and is not live at that point.\n\nThis patch changes the tracking of kill flags to allow for multiple\nflags to be removed: instead of remembering just the single / latest\nkill flag, a vector is now used to track and remove them all.\nTinyPtrVector seems ideal for this as there are only very rarely more\nthan one kill flag, and it doesn\u0027t seem to give much difference in\ncompile time.\n\nThe kill flags handling here is making this pass much more complicated\nthan it would have to be. This pass does not depend on kill flags for\nits own use, so an interesting alternative to all this handling would be\nto just remove them all. If there actually is a serious user, maybe that pass\ncould instead recompute them.\n\nAlso adding an assertion which is unrelated to kill flags, but it seems\nto make sense (according to liberal assertion policy), to verify that\nthe preceding definition is in fact identical in clearKillsForDef().\n\nFixes #117783\n",
  "tree_diff": [
    {
      "type": "modify",
      "old_id": "503e577712a7f4075ef865d26d7eb6be5bd6087b",
      "old_mode": 33188,
      "old_path": "llvm/lib/CodeGen/MachineLateInstrsCleanup.cpp",
      "new_id": "c8c8ed99d93eaa14cb99f85eb14554f3fc95e54e",
      "new_mode": 33188,
      "new_path": "llvm/lib/CodeGen/MachineLateInstrsCleanup.cpp"
    },
    {
      "type": "add",
      "old_id": "0000000000000000000000000000000000000000",
      "old_mode": 0,
      "old_path": "/dev/null",
      "new_id": "252d542f8bd08de0192e403f4e01ea9884f0ca60",
      "new_mode": 33188,
      "new_path": "llvm/test/CodeGen/SystemZ/machine-latecleanup-kills.mir"
    }
  ]
}