[turbofan] Remove ineffective optimization from ControlReducer.

This optimization just duplicates part of the ToBoolean rule in the
Typer, and it doesn't make sense to have adhoc partial typing rules in
the ControlReducer anyway.

R=jarin@chromium.org

Review URL: https://codereview.chromium.org/1189963002

Cr-Commit-Position: refs/heads/master@{#29064}

src/compiler/control-reducer.cc

@@ -212,11 +212,6 @@ class ControlReducerImpl final : public AdvancedReducer {
       default:
         break;
     }
-    if (NodeProperties::IsTyped(cond)) {
-      // If the node has a range type, check whether the range excludes 0.
-      Type* type = NodeProperties::GetBounds(cond).upper;
-      if (type->IsRange() && (type->Min() > 0 || type->Max() < 0)) return kTrue;
-    }
     return kUnknown;
   }
 

test/unittests/compiler/control-reducer-unittest.cc

@@ -145,52 +145,6 @@ TEST_F(ControlReducerTest, PhiAsInputToBranch_unknown_true) {
 }
 
 
-TEST_F(ControlReducerTest, RangeAsInputToBranch_true1) {
-  Node* p0 = Parameter(Type::Range(1, 2, zone()), 0);
-  Node* branch1 = graph()->NewNode(common()->Branch(), p0, graph()->start());
-  Node* if_true1 = graph()->NewNode(common()->IfTrue(), branch1);
-  Node* if_false1 = graph()->NewNode(common()->IfFalse(), branch1);
-  Node* merge1 = graph()->NewNode(common()->Merge(1), if_true1, if_false1);
-  Node* result = graph()->NewNode(common()->Phi(kMachInt32, 2),
-                                  jsgraph()->Int32Constant(11),
-                                  jsgraph()->Int32Constant(44), merge1);
-
-  Node* ret =
-      graph()->NewNode(common()->Return(), result, graph()->start(), merge1);
-  graph()->end()->ReplaceInput(0, ret);
-
-  ReduceGraph();
-
-  // Diamond should be folded away.
-  EXPECT_THAT(
-      graph()->end(),
-      IsEnd(IsReturn(IsInt32Constant(11), graph()->start(), graph()->start())));
-}
-
-
-TEST_F(ControlReducerTest, RangeAsInputToBranch_true2) {
-  Node* p0 = Parameter(Type::Range(-2, -1, zone()), 0);
-  Node* branch1 = graph()->NewNode(common()->Branch(), p0, graph()->start());
-  Node* if_true1 = graph()->NewNode(common()->IfTrue(), branch1);
-  Node* if_false1 = graph()->NewNode(common()->IfFalse(), branch1);
-  Node* merge1 = graph()->NewNode(common()->Merge(1), if_true1, if_false1);
-  Node* result = graph()->NewNode(common()->Phi(kMachInt32, 2),
-                                  jsgraph()->Int32Constant(11),
-                                  jsgraph()->Int32Constant(44), merge1);
-
-  Node* ret =
-      graph()->NewNode(common()->Return(), result, graph()->start(), merge1);
-  graph()->end()->ReplaceInput(0, ret);
-
-  ReduceGraph();
-
-  // Diamond should be folded away.
-  EXPECT_THAT(
-      graph()->end(),
-      IsEnd(IsReturn(IsInt32Constant(11), graph()->start(), graph()->start())));
-}
-
-
 TEST_F(ControlReducerTest, SelectPhi) {
   Node* p0 = Parameter(0);
   const MachineType kType = kMachInt32;