[PATCH] D109917: [InstCombine] Improve TryToSink for side-effecting calls that would be trivially dead

[Anna Thomas via Phabricator via llvm-commits]

anna created this revision.
anna added reviewers: reames, nikic, mkazantsev, apilipenko.
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This patch adds support to sink side-effecting calls that are legal to
sink to the successor use block. We can sink such calls as long as these
two conditions are satisfied:

1. The instruction would be trivially dead (i.e. if there were no uses of the instruction, we can remove the instruction).
2. There are no side-effecting instructions between the current one until the end of the block.

This helps with sinking allocations down to use blocks when safe to do
so (see added testcases).


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D109917

Files:
  llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
  llvm/test/Transforms/InstCombine/sink_instruction.ll

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