[turbofan] Properly emit bounds checks for typed array element loads.

src/compiler/representation-change.h

 // 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.
 
 #ifndef V8_COMPILER_REPRESENTATION_CHANGE_H_
 #define V8_COMPILER_REPRESENTATION_CHANGE_H_
 
 #include <sstream>
 
 #include "src/base/bits.h"
@@ skipping 139 matching lines @@
       }
       // int32 -> float64 -> float32
       node = jsgraph()->graph()->NewNode(op, node);
       op = machine()->TruncateFloat64ToFloat32();
     } else if (output_type & kRepTagged) {
       op = simplified()
                ->ChangeTaggedToFloat64();  // tagged -> float64 -> float32
       node = jsgraph()->graph()->NewNode(op, node);
       op = machine()->TruncateFloat64ToFloat32();
     } else if (output_type & kRepFloat64) {
-      op = machine()->ChangeFloat32ToFloat64();
+      op = machine()->TruncateFloat64ToFloat32();
     } else {
       return TypeError(node, output_type, kRepFloat32);
     }
     return jsgraph()->graph()->NewNode(op, node);
   }
 
   Node* GetFloat64RepresentationFor(Node* node, MachineTypeUnion output_type) {
     // Eagerly fold representation changes for constants.
     switch (node->opcode()) {
       case IrOpcode::kNumberConstant:
@@ skipping 254 matching lines @@
   Isolate* isolate() { return isolate_; }
   SimplifiedOperatorBuilder* simplified() { return simplified_; }
   MachineOperatorBuilder* machine() { return jsgraph()->machine(); }
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_REPRESENTATION_CHANGE_H_