Make LoadIndexedInstr for Uint32List use kUnboxedUint32 representation

runtime/vm/intermediate_language_arm.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_ARM.
 #if defined(TARGET_ARCH_ARM)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/cpu.h"
@@ skipping 1098 matching lines @@
     case kTypedDataUint8ClampedArrayCid:
     case kExternalTypedDataUint8ArrayCid:
     case kExternalTypedDataUint8ClampedArrayCid:
     case kTypedDataInt16ArrayCid:
     case kTypedDataUint16ArrayCid:
     case kOneByteStringCid:
     case kTwoByteStringCid:
       return CompileType::FromCid(kSmiCid);
 
     case kTypedDataInt32ArrayCid:
+      return Typed32BitIsSmi() ? CompileType::FromCid(kSmiCid)

[Vyacheslav Egorov (Google), 2014/09/30 15:06:01]

Any reason you don't want to support Int32List too?

[Cutch, 2014/09/30 15:39:12]

Done.

+                               : CompileType::FromCid(kMintCid);
+
     case kTypedDataUint32ArrayCid:
-      return Typed32BitIsSmi() ? CompileType::FromCid(kSmiCid)
-                                : CompileType::FromCid(kMintCid);
+      return CompileType::FromCid(kMintCid);

[Vyacheslav Egorov (Google), 2014/09/30 15:06:02]

This is not correct actually: boxing can result in both kSmiCid and kMintCid
which means this should be CompileType::Int() and ditto above for kMintCid case.

I wonder if we can create a regression test for this. Might be a bit hard
though.

[Cutch, 2014/09/30 15:39:12]

Done. Here and above.

 
     default:
       UNREACHABLE();
       return CompileType::Dynamic();
   }
 }
 
 
 Representation LoadIndexedInstr::representation() const {
   switch (class_id_) {
     case kArrayCid:
     case kImmutableArrayCid:
     case kTypedDataInt8ArrayCid:
     case kTypedDataUint8ArrayCid:
     case kTypedDataUint8ClampedArrayCid:
     case kExternalTypedDataUint8ArrayCid:
     case kExternalTypedDataUint8ClampedArrayCid:
     case kTypedDataInt16ArrayCid:
     case kTypedDataUint16ArrayCid:
     case kOneByteStringCid:
     case kTwoByteStringCid:
       return kTagged;
     case kTypedDataInt32ArrayCid:
+      return Typed32BitIsSmi() ? kTagged : kUnboxedMint;
     case kTypedDataUint32ArrayCid:
-      return Typed32BitIsSmi() ? kTagged : kUnboxedMint;
+      return kUnboxedUint32;
     case kTypedDataFloat32ArrayCid:
     case kTypedDataFloat64ArrayCid:
       return kUnboxedDouble;
     case kTypedDataInt32x4ArrayCid:
       return kUnboxedInt32x4;
     case kTypedDataFloat32x4ArrayCid:
       return kUnboxedFloat32x4;
     case kTypedDataFloat64x2ArrayCid:
       return kUnboxedFloat64x2;
     default:
@@ skipping 65 matching lines @@
       // Need register <= Q7 for float operations.
       // TODO(fschneider): Add a register policy to specify a subset of
       // registers.
       locs->set_out(0, Location::FpuRegisterLocation(Q7));
     } else {
       locs->set_out(0, Location::RequiresFpuRegister());
     }
   } else if (representation() == kUnboxedMint) {
     locs->set_out(0, Location::Pair(Location::RequiresRegister(),
                                     Location::RequiresRegister()));
+  } else if (representation() == kUnboxedUint32) {
+    locs->set_out(0, Location::RequiresRegister());
   } else {
     ASSERT(representation() == kTagged);
     locs->set_out(0, Location::RequiresRegister());
   }
   return locs;
 }
 
 
 void LoadIndexedInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   // The array register points to the backing store for external arrays.
@@ skipping 44 matching lines @@
     PairLocation* result_pair = locs()->out(0).AsPairLocation();
     const Register result1 = result_pair->At(0).reg();
     const Register result2 = result_pair->At(1).reg();
     switch (class_id()) {
       case kTypedDataInt32ArrayCid:
         // Load low word.
         __ ldr(result1, element_address);
         // Sign extend into high word.
         __ SignFill(result2, result1);
         break;
-      case kTypedDataUint32ArrayCid:
-        // Load low word.
-        __ ldr(result1, element_address);
-        // Zero high word.
-        __ eor(result2, result2, Operand(result2));
-        break;
       default:
         UNREACHABLE();
         break;
     }
     return;
   }
 
+  if (representation() == kUnboxedUint32) {
+    ASSERT(class_id() == kTypedDataUint32ArrayCid);
+    const Register result = locs()->out(0).reg();
+    __ ldr(result, element_address);
+    return;
+  }
+
   ASSERT(representation() == kTagged);
 
   const Register result = locs()->out(0).reg();
   switch (class_id()) {
     case kTypedDataInt8ArrayCid:
       ASSERT(index_scale() == 1);
       __ ldrsb(result, element_address);
       __ SmiTag(result);
       break;
     case kTypedDataUint8ArrayCid:
@@ skipping 5700 matching lines @@
   compiler->GenerateCall(token_pos(), &label, stub_kind_, locs());
 #if defined(DEBUG)
   __ LoadImmediate(R4, kInvalidObjectPointer);
   __ LoadImmediate(R5, kInvalidObjectPointer);
 #endif
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM