[turbofan] Introduce CheckIf simplified operator.

src/compiler/effect-control-linearizer.cc

Index: src/compiler/effect-control-linearizer.cc
diff --git a/src/compiler/effect-control-linearizer.cc b/src/compiler/effect-control-linearizer.cc
index ba381919298d1ccaa04366baac37e4714ac19058..1304e5410439f757d7e89e45e477aaaecf902036 100644
--- a/src/compiler/effect-control-linearizer.cc
+++ b/src/compiler/effect-control-linearizer.cc
@@ -434,6 +434,9 @@ bool EffectControlLinearizer::TryWireInStateEffect(Node* node,
     case IrOpcode::kCheckNumber:
       state = LowerCheckNumber(node, frame_state, *effect, *control);
       break;
+    case IrOpcode::kCheckIf:
+      state = LowerCheckIf(node, frame_state, *effect, *control);
+      break;
     case IrOpcode::kCheckTaggedPointer:
       state = LowerCheckTaggedPointer(node, frame_state, *effect, *control);
       break;
@@ -836,6 +839,20 @@ EffectControlLinearizer::LowerCheckNumber(Node* node, Node* frame_state,
 }
 
 EffectControlLinearizer::ValueEffectControl
+EffectControlLinearizer::LowerCheckIf(Node* node, Node* frame_state,
+                                      Node* effect, Node* control) {
+  Node* value = node->InputAt(0);
+
+  control = effect = graph()->NewNode(common()->DeoptimizeUnless(), value,
+                                      frame_state, effect, control);
+
+  // Make sure the lowered node does not appear in any use lists.
+  node->TrimInputCount(0);
+
+  return ValueEffectControl(value, effect, control);
+}
+
+EffectControlLinearizer::ValueEffectControl
 EffectControlLinearizer::LowerCheckTaggedPointer(Node* node, Node* frame_state,
                                                  Node* effect, Node* control) {
   Node* value = node->InputAt(0);