From 074bcc7643487853df21590c47c971215a31cdeb Mon Sep 17 00:00:00 2001 From: Philip Reames Date: Tue, 3 Sep 2019 21:56:17 +0000 Subject: [PATCH] [GVN] Remove a todo introduced w/rL370791 When I dug into this, it turns out to be *much* more involved than I'd realized and doesn't actually simplify anything. The general purpose of the leader table is that we want to find the most-dominating definition quickly. The problem for equivalance folding is slightly different; we want to find the most dominating *value* whose definition block dominates our use quickly. To make this change, we'd end up having to restructure the leader table (either the sorting thereof, or maybe even introducing multiple leader tables per value) and that complexity is just not worth it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@370824 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/GVN.cpp | 3 --- 1 file changed, 3 deletions(-) diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp index e71d771ce42..c57cdc4be6a 100644 --- a/lib/Transforms/Scalar/GVN.cpp +++ b/lib/Transforms/Scalar/GVN.cpp @@ -1754,9 +1754,6 @@ void GVN::assignBlockRPONumber(Function &F) { } bool GVN::replaceOperandsForInBlockEquality(Instruction *Instr) const { - // TODO: We can remove the separate ReplaceOperandsWithMap data structure in - // favor of putting equalitys into the leader table and using findLeader - // here. bool Changed = false; for (unsigned OpNum = 0; OpNum < Instr->getNumOperands(); ++OpNum) { Value *Operand = Instr->getOperand(OpNum); -- 2.50.1