[llvm-branch-commits] [ADCE][NFC] Cleanup data structures (PR #189407)

[Alexis Engelke via llvm-branch-commits]

https://github.com/aengelke created https://github.com/llvm/llvm-project/pull/189407

Cleanup used data structures:

- Replace InstInfo map with a DenseSet, the pointer to the BlockInfo is
  used only once and can be easily (and cheaply) accessed using the
  block number.

- Remove "cached" fields from block data structures -- there is no
  measurable performance benefit, but these fields do need to be
  initialized and consume memory, so remove them. In all cases, the
  information is trivially accessible from the instruction or block.