[PATCH] D136218: [DSE] Sink a memory access if it is only alive in one successor.

[luxufan via Phabricator via llvm-commits]

StephenFan created this revision.
StephenFan added reviewers: nikic, fhahn, asbirlea, efriedma.
Herald added a subscriber: hiraditya.
Herald added a project: All.
StephenFan requested review of this revision.
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.

If a memory access is only alive in one successor, sinking the instruction
of this memory access to the alive successor will make the program execute one
less instruction if it goes to dead successors(successors except the
alive successor).

Since deleting instruction is more beneficial than sinking, sinking will
be doing until we have deleted all dead instructions.

It seems to have no effect on on compile time: https://llvm-compile-time-tracker.com/compare.php?from=6eb40bf51b768672218539935f60ce55ae6ad750&to=e8bccfd7a3c58f3287f7da7ab3e2582ec270b0f4&stat=instructions


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D136218

Files:
  llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
  llvm/test/Transforms/DeadStoreElimination/multiblock-multipath.ll
  llvm/test/Transforms/DeadStoreElimination/multiblock-simple.ll
  llvm/test/Transforms/DeadStoreElimination/multiblock-sink.ll

-------------- next part --------------
A non-text attachment was scrubbed...
Name: D136218.468760.patch
Type: text/x-patch
Size: 16545 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20221019/f9bfc45d/attachment.bin>