[turbofan] Introduce DeoptimizeIf And DeoptimizeUnless common operators.

src/compiler/common-operator-reducer.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/common-operator-reducer.h"
 
 #include <algorithm>
 
 #include "src/compiler/common-operator.h"
 #include "src/compiler/graph.h"
@@ skipping 39 matching lines @@
       graph_(graph),
       common_(common),
       machine_(machine),
       dead_(graph->NewNode(common->Dead())) {}
 
 
 Reduction CommonOperatorReducer::Reduce(Node* node) {
   switch (node->opcode()) {
     case IrOpcode::kBranch:
       return ReduceBranch(node);
+    case IrOpcode::kDeoptimizeIf:
+    case IrOpcode::kDeoptimizeUnless:
+      return ReduceDeoptimizeConditional(node);
     case IrOpcode::kMerge:
       return ReduceMerge(node);
     case IrOpcode::kEffectPhi:
       return ReduceEffectPhi(node);
     case IrOpcode::kPhi:
       return ReducePhi(node);
     case IrOpcode::kReturn:
       return ReduceReturn(node);
     case IrOpcode::kSelect:
       return ReduceSelect(node);
@@ skipping 46 matching lines @@
       case IrOpcode::kIfFalse:
         Replace(use, (decision == Decision::kFalse) ? control : dead());
         break;
       default:
         UNREACHABLE();
     }
   }
   return Replace(dead());
 }
 
+Reduction CommonOperatorReducer::ReduceDeoptimizeConditional(Node* node) {
+  DCHECK(node->opcode() == IrOpcode::kDeoptimizeIf ||
+         node->opcode() == IrOpcode::kDeoptimizeUnless);
+  bool condition_is_true = node->opcode() == IrOpcode::kDeoptimizeUnless;
+  Node* condition = NodeProperties::GetValueInput(node, 0);
+  Node* frame_state = NodeProperties::GetValueInput(node, 1);
+  Node* effect = NodeProperties::GetEffectInput(node);
+  Node* control = NodeProperties::GetControlInput(node);
+  // Swap DeoptimizeIf/DeoptimizeUnless on {node} if {cond} is a BooleaNot
+  // and use the input to BooleanNot as new condition for {node}.  Note we
+  // assume that {cond} was already properly optimized before we get here
+  // (as guaranteed by the graph reduction logic).
+  if (condition->opcode() == IrOpcode::kBooleanNot) {
+    NodeProperties::ReplaceValueInput(node, condition->InputAt(0), 0);
+    NodeProperties::ChangeOp(node, condition_is_true
+                                       ? common()->DeoptimizeIf()
+                                       : common()->DeoptimizeUnless());
+    return Changed(node);
+  }
+  Decision const decision = DecideCondition(condition);
+  if (decision == Decision::kUnknown) return NoChange();
+  if (condition_is_true == (decision == Decision::kTrue)) {
+    return Replace(control);
+  }
+  control = graph()->NewNode(common()->Deoptimize(DeoptimizeKind::kEager),
+                             frame_state, effect, control);
+  // TODO(bmeurer): This should be on the AdvancedReducer somehow.
+  NodeProperties::MergeControlToEnd(graph(), common(), control);
+  Revisit(graph()->end());
+  return Replace(dead());
+}
 
 Reduction CommonOperatorReducer::ReduceMerge(Node* node) {
   DCHECK_EQ(IrOpcode::kMerge, node->opcode());
   //
   // Check if this is a merge that belongs to an unused diamond, which means
   // that:
   //
   //  a) the {Merge} has no {Phi} or {EffectPhi} uses, and
   //  b) the {Merge} has two inputs, one {IfTrue} and one {IfFalse}, which are
   //     both owned by the Merge, and
@@ skipping 250 matching lines @@
   node->ReplaceInput(0, a);
   node->ReplaceInput(1, b);
   node->TrimInputCount(2);
   NodeProperties::ChangeOp(node, op);
   return Changed(node);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8