SimplifyCFG: Add Trunc, ZExt and SExt to the list of cheap instructions for phi node folding

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130526 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Utils/SimplifyCFG.cpp

@@ -261,6 +261,9 @@ static bool DominatesMergePoint(Value *V, BasicBlock *BB,
   case Instruction::LShr:
   case Instruction::AShr:
   case Instruction::ICmp:
+  case Instruction::Trunc:
+  case Instruction::ZExt:
+  case Instruction::SExt:
     break;   // These are all cheap and non-trapping instructions.
   }