[all-commits] [llvm/llvm-project] 3478d6: [DSE] Check for whole object overwrite even if dea...

[Nikita Popov via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 3478d64ee4bf350d98da9734aee1bd0faab60da9
      https://github.com/llvm/llvm-project/commit/3478d64ee4bf350d98da9734aee1bd0faab60da9
  Author: Nikita Popov <npopov at redhat.com>
  Date:   2022-01-03 (Mon, 03 Jan 2022)

  Changed paths:
    M llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
    M llvm/test/Transforms/DeadStoreElimination/trivial-dse-calls.ll

  Log Message:
  -----------
  [DSE] Check for whole object overwrite even if dead store size not known

If the killing store overwrites the whole object, we know that the
preceding store is dead, regardless of the accessed offset or size.
This case was previously only handled if the size of the dead store
was also known.

This allows us to perform conventional DSE for calls that write to
an argument (but without known size).

Differential Revision: https://reviews.llvm.org/D116267