[all-commits] [llvm/llvm-project] d1a1cc: [DSE, MemorySSA] Do not use callCapturesBefore in i...

[Florian Hahn via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: d1a1cce5b130630df0c821e8cafe5f683ccccb90
      https://github.com/llvm/llvm-project/commit/d1a1cce5b130630df0c821e8cafe5f683ccccb90
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2020-08-24 (Mon, 24 Aug 2020)

  Changed paths:
    M llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp

  Log Message:
  -----------
  [DSE,MemorySSA] Do not use callCapturesBefore in isReadClobber.

Using callCapturesBefore potentially improves the precision and the
number of stores we can remove. But in practice, it seems to have very
little impact in terms of stores removed. For example, for
SPEC2000/SPEC2006/MultiSource with -O3 -flto, ~50 more stores are
removed (out of ~26900 stores removed). But in terms of compile-time, it
is very expensive and the patch gives substantial compile-time
improvements: Geomean O3 -0.24%, ReleaseThinLTO -0.47%, ReleaseLTO-g
-0.39%.

http://llvm-compile-time-tracker.com/compare.php?from=612a0bff88ed906c83b82f079d4c49e5fecfb9d0&to=e6c86b96d20d97dd88e903a409bd8d39b6114312&stat=instructions