H-BuildIncrement should make use of available type feedback

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 95090d5160ca096a9391e6d39d10548a37ea193a..968340d725f0be09be8838d6a1d3e235d27a62f8 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -7494,7 +7494,12 @@ HInstruction* HOptimizedGraphBuilder::BuildIncrement(
   HConstant* delta = (expr->op() == Token::INC)
       ? graph()->GetConstant1()
       : graph()->GetConstantMinus1();
-  HInstruction* instr = Add<HAdd>(Top(), delta);
+  HInstruction* instr = AddUncasted<HAdd>(Top(), delta);
+  if (instr->IsAdd()) {
+    HAdd* add = HAdd::cast(instr);
+    add->set_observed_input_representation(1, rep);
+    add->set_observed_input_representation(2, Representation::Smi());
+  }
   instr->SetFlag(HInstruction::kCannotBeTagged);
   instr->ClearAllSideEffects();
   return instr;