[PATCH] D56772: [MIR] Add simple PRE pass to MachineCSE

[Hal Finkel via Phabricator via llvm-commits]

hfinkel added inline comments.


================
Comment at: lib/CodeGen/MachineCSE.cpp:800
+      if (BB != nullptr && BB1 != nullptr &&
+          (isPotentiallyReachable(BB1, BB) ||
+           isPotentiallyReachable(BB, BB1))) {
----------------
Are these calls expensive?

SingleSour.../Benchmarks/Misc-C++/Large/ray     0.68              0.74             7.6%

That 7% increase in compile time, and a few other others, look significant.

(Maybe there's something you can cache?)


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D56772/new/

https://reviews.llvm.org/D56772