[PATCH] D132408: [SimplifyCFG] accumulate bonus insts cost

[Nikita Popov via Phabricator via llvm-commits]

nikic added reviewers: spatel, fhahn, nikic.
nikic added a comment.

Do you have any numbers for the impact of this change? I suspect (but haven't checked) that it may be quite significant, because the current tiny bonus inst threshold (1) is tuned for the current implementation, and this patch will result in much less common dest folding than would be desirable.



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Comment at: llvm/lib/Transforms/Utils/SimplifyCFG.cpp:211
+    NumBonusInsts.insert({BB, 0});
+    Loc = NumBonusInsts.find(BB);
+  }
----------------
insert returns the iterator, no need to call find again.


================
Comment at: llvm/lib/Transforms/Utils/SimplifyCFG.cpp:219
+    return 0;
+  return Loc->second;
+}
----------------
You can use lookup() here, which will return 0 if not found.


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https://reviews.llvm.org/D132408