[turbofan] Verify nodes without kNoThrow have only IfSuccess or IfException uses.

src/compiler/verifier.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/verifier.h"
 
 #include <algorithm>
 #include <deque>
 #include <queue>
 #include <sstream>
@@ skipping 131 matching lines @@
       Node* effect = NodeProperties::GetEffectInput(node);
       CheckOutput(effect, node, effect->op()->EffectOutputCount(), "effect");
     }
 
     // Verify all control inputs are control nodes.
     for (int i = 0; i < control_count; ++i) {
       Node* control = NodeProperties::GetControlInput(node, i);
       CheckOutput(control, node, control->op()->ControlOutputCount(),
                   "control");
     }
+
+    // Verify that 2 control outputs is either a Branch or is followed by
+    // IfSuccess/IfException.
+    if (node->op()->ControlOutputCount() != 1 &&
+        node->opcode() != IrOpcode::kBranch &&
+        node->opcode() != IrOpcode::kSwitch) {

[bgeron, 2016/08/11 10:56:18]

Changed.

+      int count_success = 0, count_exception = 0;
+      for (Edge edge : node->use_edges()) {
+        if (!NodeProperties::IsControlEdge(edge)) {
+          continue;
+        }
+        Node* control_use = edge.from();
+        CHECK_EXTRA(control_use->opcode() == IrOpcode::kIfSuccess ||
+                        control_use->opcode() == IrOpcode::kIfException,
+                    "#%d:%s should be followed by IfSuccess/IfException, but "
+                    "is followed by #%d:%s",
+                    node->id(), node->op()->mnemonic(), control_use->id(),
+                    control_use->op()->mnemonic());
+        if (control_use->opcode() == IrOpcode::kIfSuccess) ++count_success;
+        if (control_use->opcode() == IrOpcode::kIfException) ++count_exception;
+        CHECK_LE(count_success, 1);
+        CHECK_LE(count_exception, 1);
+      }
+    }
   }
 
   switch (node->opcode()) {
     case IrOpcode::kStart:
       // Start has no inputs.
       CHECK_EQ(0, input_count);
       // Type is a tuple.
       // TODO(rossberg): Multiple outputs are currently typed as Internal.
       CheckUpperIs(node, Type::Internal());
       break;
@@ skipping 1414 matching lines @@
          replacement->op()->EffectOutputCount() > 0);
   DCHECK(!NodeProperties::IsFrameStateEdge(edge) ||
          replacement->opcode() == IrOpcode::kFrameState);
 }
 
 #endif  // DEBUG
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8