[turbofan] Graph assembler label: no need for explicit merge count anymore.

Bug: v8:5267
Change-Id: Ib103fbc3cabaac191dde817724308b19361c443b
Reviewed-on: https://chromium-review.googlesource.com/640385Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47670}

src/compiler/graph-assembler.h

@@ -93,7 +93,7 @@ class GraphAssemblerLabel {
 
   template <typename... Reps>
   explicit GraphAssemblerLabel(GraphAssemblerLabelType is_deferred,
-                               size_t merge_count, Reps... reps)
+                               Reps... reps)
       : is_deferred_(is_deferred == GraphAssemblerLabelType::kDeferred) {
     STATIC_ASSERT(VarCount == sizeof...(reps));
     MachineRepresentation reps_array[] = {MachineRepresentation::kNone,
@@ -130,28 +130,23 @@ class GraphAssembler {
 
   void Reset(Node* effect, Node* control);
 
-  // Create non-deferred label with statically known number of incoming
-  // gotos/branches.
-  template <size_t MergeCount, typename... Reps>
-  static GraphAssemblerLabel<sizeof...(Reps)> MakeLabel(Reps... reps) {
-    return GraphAssemblerLabel<sizeof...(Reps)>(
-        GraphAssemblerLabelType::kNonDeferred, MergeCount, reps...);
+  // Create label.
+  template <typename... Reps>
+  static GraphAssemblerLabel<sizeof...(Reps)> MakeLabelFor(
+      GraphAssemblerLabelType is_deferred, Reps... reps) {
+    return GraphAssemblerLabel<sizeof...(Reps)>(is_deferred, reps...);
   }
 
-  // Create deferred label with statically known number of incoming
-  // gotos/branches.
-  template <size_t MergeCount, typename... Reps>
-  static GraphAssemblerLabel<sizeof...(Reps)> MakeDeferredLabel(Reps... reps) {
-    return GraphAssemblerLabel<sizeof...(Reps)>(
-        GraphAssemblerLabelType::kDeferred, MergeCount, reps...);
+  // Convenience wrapper for creating non-deferred labels.
+  template <typename... Reps>
+  static GraphAssemblerLabel<sizeof...(Reps)> MakeLabel(Reps... reps) {
+    return MakeLabelFor(GraphAssemblerLabelType::kNonDeferred, reps...);
   }
 
-  // Create label with number of incoming branches supplied at runtime.
+  // Convenience wrapper for creating deferred labels.
   template <typename... Reps>
-  GraphAssemblerLabel<sizeof...(Reps)> MakeLabelFor(
-      GraphAssemblerLabelType is_deferred, size_t merge_count, Reps... reps) {
-    return GraphAssemblerLabel<sizeof...(Reps)>(is_deferred, merge_count,
-                                                reps...);
+  static GraphAssemblerLabel<sizeof...(Reps)> MakeDeferredLabel(Reps... reps) {
+    return MakeLabelFor(GraphAssemblerLabelType::kDeferred, reps...);
   }
 
   // Value creation.

src/compiler/memory-optimizer.cc

@@ -195,8 +195,8 @@ void MemoryOptimizer::VisitAllocate(Node* node, AllocationState const* state) {
       group->Add(value);
       state = AllocationState::Open(group, state_size, top, zone());
     } else {
-      auto call_runtime = __ MakeDeferredLabel<1>();
-      auto done = __ MakeLabel<2>(MachineType::PointerRepresentation());
+      auto call_runtime = __ MakeDeferredLabel();
+      auto done = __ MakeLabel(MachineType::PointerRepresentation());
 
       // Setup a mutable reservation size node; will be patched as we fold
       // additional allocations into this new group.
@@ -252,8 +252,8 @@ void MemoryOptimizer::VisitAllocate(Node* node, AllocationState const* state) {
       state = AllocationState::Open(group, object_size, top, zone());
     }
   } else {
-    auto call_runtime = __ MakeDeferredLabel<1>();
-    auto done = __ MakeLabel<2>(MachineRepresentation::kTaggedPointer);
+    auto call_runtime = __ MakeDeferredLabel();
+    auto done = __ MakeLabel(MachineRepresentation::kTaggedPointer);
 
     // Load allocation top and limit.
     Node* top =