[turbofan] Change End to take a variable number of inputs.

src/compiler/js-inlining.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/js-inlining.h"
 
 #include "src/ast.h"
 #include "src/ast-numbering.h"
 #include "src/compiler/all-nodes.h"
 #include "src/compiler/ast-graph-builder.h"
@@ skipping 147 matching lines @@
           edge.UpdateTo(effect);
         } else if (NodeProperties::IsControlEdge(edge)) {
           edge.UpdateTo(control);
         } else {
           UNREACHABLE();
         }
         break;
     }
   }
 
-  // TODO(turbofan): This can be unified once End takes a variable number of
-  // inputs.
-  Node* value_output;
-  Node* effect_output;
-  Node* control_output;
-
-  Node* final_merge = NodeProperties::GetControlInput(end);
-  if (final_merge->opcode() == IrOpcode::kReturn) {
-    value_output = NodeProperties::GetValueInput(final_merge, 0);
-    effect_output = NodeProperties::GetEffectInput(final_merge, 0);
-    control_output = NodeProperties::GetControlInput(final_merge, 0);
-  } else {
-    NodeVector values(local_zone_);
-    NodeVector effects(local_zone_);
-    NodeVector controls(local_zone_);
-    DCHECK_EQ(IrOpcode::kMerge, final_merge->opcode());
-    for (Node* const input : final_merge->inputs()) {
-      switch (input->opcode()) {
-        case IrOpcode::kReturn:
-          values.push_back(NodeProperties::GetValueInput(input, 0));
-          effects.push_back(NodeProperties::GetEffectInput(input));
-          controls.push_back(NodeProperties::GetControlInput(input));
-          break;
-        default:
-          // TODO(turbofan): Handle Throw, Terminate and Deoptimize here.
-          UNREACHABLE();
-          break;
-      }
+  NodeVector values(local_zone_);
+  NodeVector effects(local_zone_);
+  NodeVector controls(local_zone_);
+  for (Node* const input : end->inputs()) {
+    switch (input->opcode()) {
+      case IrOpcode::kReturn:
+        values.push_back(NodeProperties::GetValueInput(input, 0));
+        effects.push_back(NodeProperties::GetEffectInput(input));
+        controls.push_back(NodeProperties::GetControlInput(input));
+        break;
+      default:
+        // TODO(turbofan): Handle Throw, Terminate and Deoptimize here.
+        UNREACHABLE();
+        break;
     }
-    DCHECK_NE(0u, values.size());
-    DCHECK_EQ(values.size(), effects.size());
-    DCHECK_EQ(values.size(), controls.size());
-    int const input_count = static_cast<int>(controls.size());
-    control_output = jsgraph_->graph()->NewNode(
-        jsgraph_->common()->Merge(input_count), input_count, &controls.front());
-    values.push_back(control_output);
-    effects.push_back(control_output);
-    value_output = jsgraph_->graph()->NewNode(
-        jsgraph_->common()->Phi(kMachAnyTagged, input_count),
-        static_cast<int>(values.size()), &values.front());
-    effect_output = jsgraph_->graph()->NewNode(
-        jsgraph_->common()->EffectPhi(input_count),
-        static_cast<int>(effects.size()), &effects.front());
   }
+  DCHECK_NE(0u, values.size());
+  DCHECK_EQ(values.size(), effects.size());
+  DCHECK_EQ(values.size(), controls.size());
+  int const input_count = static_cast<int>(controls.size());
+  Node* control_output = jsgraph_->graph()->NewNode(
+      jsgraph_->common()->Merge(input_count), input_count, &controls.front());

[Michael Starzinger, 2015/05/26 10:28:05]

This will create a singleton Merge as well as singleton Phi and EffectPhi nodes
in case values.size == 1, is this working as intended?

[Benedikt Meurer, 2015/05/26 10:29:31]

Yes. My plan is to optimize this away later. For now it's ok since the control
reducer will take care of those immediately.

+  values.push_back(control_output);
+  effects.push_back(control_output);
+  Node* value_output = jsgraph_->graph()->NewNode(
+      jsgraph_->common()->Phi(kMachAnyTagged, input_count),
+      static_cast<int>(values.size()), &values.front());
+  Node* effect_output = jsgraph_->graph()->NewNode(
+      jsgraph_->common()->EffectPhi(input_count),
+      static_cast<int>(effects.size()), &effects.front());
 
   ReplaceWithValue(call, value_output, effect_output, control_output);
 
   return Changed(value_output);
 }
 
 
 Node* JSInliner::CreateArgumentsAdaptorFrameState(JSCallFunctionAccessor* call,
                                                   Zone* temp_zone) {
   const Operator* op = jsgraph_->common()->FrameState(
@@ skipping 94 matching lines @@
       }
     }
   }
 
   return InlineCall(node, start, end);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8