[all-commits] [llvm/llvm-project] aa0b92: [GlobalISel][IRTranslator] Move line zero DebugLoc...

[Amara Emerson via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: aa0b9200e8c5dea43c9ada2085a3061f4da70802
      https://github.com/llvm/llvm-project/commit/aa0b9200e8c5dea43c9ada2085a3061f4da70802
  Author: Amara Emerson <amara at apple.com>
  Date:   2021-04-28 (Wed, 28 Apr 2021)

  Changed paths:
    M llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp

  Log Message:
  -----------
  [GlobalISel][IRTranslator] Move line zero DebugLoc creation to constant translation. NFC.

This is a compile time optimization. DILocation:get() is expensive to call, and
we were calling it to create a line zero debug loc for *every* instruction we
translated. We only really need to do this just before we build constants in the
entry block, so I moved this code there. This reduces the LLVM -O0 codegen time
of sqlite3 IR by around 0.7% instructions executed and by about ~2% in CPU time.

We can probably do better with a more involved change, since the reason we need
to create one for each new constant is because we're using the debug scope and
inlined-at loc. If we just use a single instruction's scope and drop the
inlined-at, we can just cache these and have them be free.