On Ia32 optimistically assume that results from int32 and uint32 array loads fit into Smi. Only if …

runtime/vm/intermediate_language_ia32.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_IA32.
 #if defined(TARGET_ARCH_IA32)
 
 #include "vm/intermediate_language.h"
 
 #include "lib/error.h"
@@ skipping 1096 matching lines @@
     case kUint8ClampedArrayCid:
     case kExternalUint8ArrayCid:
     case kInt16ArrayCid:
     case kUint16ArrayCid:
     case kOneByteStringCid:
     case kTwoByteStringCid:
       return kSmiCid;
     case kInt32ArrayCid:
     case kUint32ArrayCid:
       // Result can be smi or mint when boxed.
-      return kDynamicCid;
+      // Optimistic assumption that result is Smi means that the instruction
+      // can deoptimize.
+      return CanDeoptimize() ? kSmiCid : kDynamicCid;
     default:
       UNIMPLEMENTED();
       return kDynamicCid;
   }
 }
 
 
 Representation LoadIndexedInstr::representation() const {
   switch (class_id_) {
     case kArrayCid:
     case kImmutableArrayCid:
     case kInt8ArrayCid:
     case kUint8ArrayCid:
     case kUint8ClampedArrayCid:
     case kExternalUint8ArrayCid:
     case kInt16ArrayCid:
     case kUint16ArrayCid:
     case kOneByteStringCid:
     case kTwoByteStringCid:
       return kTagged;
     case kInt32ArrayCid:
     case kUint32ArrayCid:
-      return kUnboxedMint;
+      // Optimistic assumption that result is Smi means that the instruction
+      // can deoptimize.
+      return CanDeoptimize() ? kTagged : kUnboxedMint;
     case kFloat32ArrayCid :
     case kFloat64ArrayCid :
       return kUnboxedDouble;
     default:
       UNIMPLEMENTED();
       return kTagged;
   }
 }
 
 
@@ skipping 95 matching lines @@
       break;
     case kInt16ArrayCid:
       __ movsxw(result, element_address);
       __ SmiTag(result);
       break;
     case kUint16ArrayCid:
     case kTwoByteStringCid:
       __ movzxw(result, element_address);
       __ SmiTag(result);
       break;
+    case kInt32ArrayCid: {
+        Label* deopt = compiler->AddDeoptStub(deopt_id(), kDeoptInt32Load);
+        __ movl(result, element_address);
+        // Verify that the signed value in 'result' can fit inside a Smi.
+        __ cmpl(result, Immediate(0xC0000000));
+        __ j(NEGATIVE, deopt);
+        __ SmiTag(result);
+      }
+      break;
+    case kUint32ArrayCid: {
+        Label* deopt = compiler->AddDeoptStub(deopt_id(), kDeoptUint32Load);
+        __ movl(result, element_address);
+        // Verify that the unsigned value in 'result' can fit inside a Smi.
+        __ testl(result, Immediate(0xC0000000));
+        __ j(NOT_ZERO, deopt);
+        __ SmiTag(result);
+      }
+      break;
     default:
       ASSERT((class_id() == kArrayCid) || (class_id() == kImmutableArrayCid));
       __ movl(result, element_address);
       break;
   }
 }
 
 
 Representation StoreIndexedInstr::RequiredInputRepresentation(
     intptr_t idx) const {
@@ skipping 2080 matching lines @@
                          PcDescriptors::kOther,
                          locs());
   __ Drop(2);  // Discard type arguments and receiver.
 }
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_IA32