[turbofan] Introduce a dedicated CheckBounds operator.

src/compiler/effect-control-linearizer.cc

 // Copyright 2015 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/effect-control-linearizer.h"
 
 #include "src/code-factory.h"
 #include "src/compiler/access-builder.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/linkage.h"
@@ skipping 398 matching lines @@
       break;
     case IrOpcode::kChangeTaggedToUint32:
       state = LowerChangeTaggedToUint32(node, *effect, *control);
       break;
     case IrOpcode::kChangeTaggedToFloat64:
       state = LowerChangeTaggedToFloat64(node, *effect, *control);
       break;
     case IrOpcode::kTruncateTaggedToFloat64:
       state = LowerTruncateTaggedToFloat64(node, *effect, *control);
       break;
+    case IrOpcode::kCheckBounds:
+      state = LowerCheckBounds(node, frame_state, *effect, *control);
+      break;
     case IrOpcode::kCheckedUint32ToInt32:
       state = LowerCheckedUint32ToInt32(node, frame_state, *effect, *control);
       break;
     case IrOpcode::kCheckedFloat64ToInt32:
       state = LowerCheckedFloat64ToInt32(node, frame_state, *effect, *control);
       break;
     case IrOpcode::kCheckedTaggedToInt32:
       state = LowerCheckedTaggedToInt32(node, frame_state, *effect, *control);
       break;
     case IrOpcode::kCheckedTaggedToFloat64:
@@ skipping 329 matching lines @@
 
   control = graph()->NewNode(common()->Merge(2), if_true, if_false);
   effect = graph()->NewNode(common()->EffectPhi(2), etrue, efalse, control);
   value = graph()->NewNode(common()->Phi(MachineRepresentation::kFloat64, 2),
                            vtrue, vfalse, control);
 
   return ValueEffectControl(value, effect, control);
 }
 
 EffectControlLinearizer::ValueEffectControl
+EffectControlLinearizer::LowerCheckBounds(Node* node, Node* frame_state,
+                                          Node* effect, Node* control) {
+  Node* index = node->InputAt(0);
+  Node* limit = node->InputAt(1);
+
+  Node* check = graph()->NewNode(machine()->Uint32LessThan(), index, limit);
+  control = effect = graph()->NewNode(common()->DeoptimizeUnless(), check,
+                                      frame_state, effect, control);
+
+  // Make sure the lowered node does not appear in any use lists.
+  node->TrimInputCount(0);
+
+  return ValueEffectControl(index, effect, control);
+}
+
+EffectControlLinearizer::ValueEffectControl
 EffectControlLinearizer::LowerCheckedUint32ToInt32(Node* node,
                                                    Node* frame_state,
                                                    Node* effect,
                                                    Node* control) {
   Node* value = node->InputAt(0);
   Node* max_int = jsgraph()->Int32Constant(std::numeric_limits<int32_t>::max());
   Node* is_safe =
       graph()->NewNode(machine()->Uint32LessThanOrEqual(), value, max_int);
   control = effect = graph()->NewNode(common()->DeoptimizeUnless(), is_safe,
                                       frame_state, effect, control);
@@ skipping 67 matching lines @@
   Node* branch =
       graph()->NewNode(common()->Branch(BranchHint::kTrue), check, control);
 
   // In the Smi case, just convert to int32.
   Node* if_true = graph()->NewNode(common()->IfTrue(), branch);
   Node* etrue = effect;
   Node* vtrue = ChangeSmiToInt32(value);
 
   // In the non-Smi case, check the heap numberness, load the number and convert
   // to int32.
-  // TODO(jarin) Propagate/handle possible truncations here.
   Node* if_false = graph()->NewNode(common()->IfFalse(), branch);
-  ValueEffectControl number_state = BuildCheckedHeapNumberOrOddballToFloat64(
-      value, frame_state, effect, if_false);
-  number_state =
-      BuildCheckedFloat64ToInt32(number_state.value, frame_state,
-                                 number_state.effect, number_state.control);
+  Node* efalse = effect;
+  Node* vfalse;
+  {
+    Node* value_map = efalse =
+        graph()->NewNode(simplified()->LoadField(AccessBuilder::ForMap()),
+                         value, efalse, if_false);
+    Node* check = graph()->NewNode(machine()->WordEqual(), value_map,
+                                   jsgraph()->HeapNumberMapConstant());
+    if_false = efalse = graph()->NewNode(common()->DeoptimizeUnless(), check,
+                                         frame_state, efalse, if_false);
+    vfalse = efalse = graph()->NewNode(
+        simplified()->LoadField(AccessBuilder::ForHeapNumberValue()), value,
+        efalse, if_false);
+    ValueEffectControl state =
+        BuildCheckedFloat64ToInt32(vfalse, frame_state, efalse, if_false);
+    if_false = state.control;
+    efalse = state.effect;
+    vfalse = state.value;
+  }
 
-  Node* merge =
-      graph()->NewNode(common()->Merge(2), if_true, number_state.control);
-  Node* effect_phi = graph()->NewNode(common()->EffectPhi(2), etrue,
-                                      number_state.effect, merge);
-  Node* result =
-      graph()->NewNode(common()->Phi(MachineRepresentation::kWord32, 2), vtrue,
-                       number_state.value, merge);
+  control = graph()->NewNode(common()->Merge(2), if_true, if_false);
+  effect = graph()->NewNode(common()->EffectPhi(2), etrue, efalse, control);
+  value = graph()->NewNode(common()->Phi(MachineRepresentation::kWord32, 2),
+                           vtrue, vfalse, control);
 
   // Make sure the lowered node does not appear in any use lists.
   node->TrimInputCount(0);
 
-  return ValueEffectControl(result, effect_phi, merge);
+  return ValueEffectControl(value, effect, control);
 }
 
 EffectControlLinearizer::ValueEffectControl
 EffectControlLinearizer::BuildCheckedHeapNumberOrOddballToFloat64(
     Node* value, Node* frame_state, Node* effect, Node* control) {
   Node* value_map = effect = graph()->NewNode(
       simplified()->LoadField(AccessBuilder::ForMap()), value, effect, control);
   Node* check_number = graph()->NewNode(machine()->WordEqual(), value_map,
                                         jsgraph()->HeapNumberMapConstant());
 
@@ skipping 660 matching lines @@
         isolate(), graph()->zone(), callable.descriptor(), 0, flags,
         Operator::kNoThrow);
     to_number_operator_.set(common()->Call(desc));
   }
   return to_number_operator_.get();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8