[turbofan] Eliminate typed array bounds checks if both key and length are constant.

src/compiler/simplified-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/generic-node-inl.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/machine-operator.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/simplified-operator-reducer.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
+SimplifiedOperatorReducer::SimplifiedOperatorReducer(JSGraph* jsgraph)
+    : jsgraph_(jsgraph), simplified_(jsgraph->zone()) {}
+
+
 SimplifiedOperatorReducer::~SimplifiedOperatorReducer() {}
 
 
 Reduction SimplifiedOperatorReducer::Reduce(Node* node) {
   switch (node->opcode()) {
     case IrOpcode::kBooleanNot: {
       HeapObjectMatcher<HeapObject> m(node->InputAt(0));
       if (m.Is(Unique<HeapObject>::CreateImmovable(factory()->false_value()))) {
         return Replace(jsgraph()->TrueConstant());
       }
@@ skipping 63 matching lines @@
                       m.node()->InputAt(0));
       }
       if (m.IsChangeUint32ToTagged()) return Replace(m.node()->InputAt(0));
       break;
     }
     case IrOpcode::kChangeUint32ToTagged: {
       Uint32Matcher m(node->InputAt(0));
       if (m.HasValue()) return ReplaceNumber(FastUI2D(m.Value()));
       break;
     }
+    case IrOpcode::kLoadElement: {
+      ElementAccess access = ElementAccessOf(node->op());
+      if (access.bounds_check == kTypedArrayBoundsCheck) {
+        NumericValueMatcher mkey(node->InputAt(1));
+        NumericValueMatcher mlength(node->InputAt(2));
+        if (mkey.HasValue() && mlength.HasValue()) {
+          // Skip the typed array bounds check if key and length are constant.
+          if (mkey.Value() < mlength.Value()) {
+            access.bounds_check = kNoBoundsCheck;
+            node->set_op(simplified()->LoadElement(access));
+            return Changed(node);
+          }
+        }
+      }
+      break;
+    }
+    case IrOpcode::kStoreElement: {
+      ElementAccess access = ElementAccessOf(node->op());
+      if (access.bounds_check == kTypedArrayBoundsCheck) {
+        NumericValueMatcher mkey(node->InputAt(1));
+        NumericValueMatcher mlength(node->InputAt(2));
+        if (mkey.HasValue() && mlength.HasValue()) {
+          // Skip the typed array bounds check if key and length are constant.
+          if (mkey.Value() < mlength.Value()) {
+            access.bounds_check = kNoBoundsCheck;
+            node->set_op(simplified()->StoreElement(access));
+            return Changed(node);
+          }
+        }
+      }
+      break;
+    }
     default:
       break;
   }
   return NoChange();
 }
 
 
 Reduction SimplifiedOperatorReducer::Change(Node* node, const Operator* op,
                                             Node* a) {
   node->set_op(op);
@@ skipping 30 matching lines @@
 }
 
 
 MachineOperatorBuilder* SimplifiedOperatorReducer::machine() const {
   return jsgraph()->machine();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8