[PATCH] D58401: [MachineCSE] Improve MachineCSE profitability heuristics for better compile time.

[Huihui Zhang via Phabricator via llvm-commits]

huihuiz created this revision.
huihuiz added reviewers: mzolotukhin, davide, efriedma, spatel.
huihuiz added a project: LLVM.
Herald added a subscriber: jdoerfert.

This patch introduces ProfitableSet to cache the results of profitability checks.
If a common subexpression machine instruction (CSMI) has been identified as
profitable before, then this CSMI tend to be profitable later on, unless a machine
instruction (MI) is not profitable for common subexpression elimination.

This fixes pr37277
Compile time went down from 32s to 13s.


Repository:
  rL LLVM

https://reviews.llvm.org/D58401

Files:
  lib/CodeGen/MachineCSE.cpp

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