[PATCH] D32433: Compute safety information in a much finer granularity.

[Eli Friedman via Phabricator via llvm-commits]

efriedma added inline comments.


================
Comment at: llvm/trunk/lib/Transforms/Utils/LoopUtils.cpp:1050
+  for (Instruction *ExitInst : SafetyInfo->EarlyExits)
+    if (!DT->dominates(&Inst, ExitInst))
+      return false;
----------------
This could be slow: if the two instructions are in the same basic block, dominates() will iterate over the whole block. And you don't attempt to prune the EarlyExits list, which could make LICM O(N^3) overall for a large loop with a single basic block.

I guess we'll see if it matters in practice.


Repository:
  rL LLVM

https://reviews.llvm.org/D32433