[all-commits] [llvm/llvm-project] 3f148e: [LiveDebugValues] Visit open var locs just once in...

[Vedant Kumar via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 3f148eabe0977228410090951cdb236d881eebcd
      https://github.com/llvm/llvm-project/commit/3f148eabe0977228410090951cdb236d881eebcd
  Author: Vedant Kumar <vsk at apple.com>
  Date:   2020-02-17 (Mon, 17 Feb 2020)

  Changed paths:
    M llvm/lib/CodeGen/LiveDebugValues.cpp

  Log Message:
  -----------
  [LiveDebugValues] Visit open var locs just once in transferRegisterDef, NFC

For a file in WebKit, this brings the time spent in LiveDebugValues down
from 16 minutes to 2 minutes. The reduction comes from iterating the set
of open variable locations just once in transferRegisterDef. Post-patch,
the most expensive item inside of transferRegisterDef is a call to
VarLoc::isDescribedByReg, which we have to do.

Testing: I built LNT using the Os-g cmake cache with & without this
patch, then diffed the object files to verify there was no binary diff.

rdar://59446577

Differential Revision: https://reviews.llvm.org/D74633