Make LoadIndexedInstr for Uint32List use kUnboxedUint32 representation

runtime/vm/intermediate_language_x64.cc

Index: runtime/vm/intermediate_language_x64.cc
diff --git a/runtime/vm/intermediate_language_x64.cc b/runtime/vm/intermediate_language_x64.cc
index 741698aceb24da4e444c8194a451bb5c3b2e3460..871e82861a090d7f7a831118d3e37442374bdfb7 100644
--- a/runtime/vm/intermediate_language_x64.cc
+++ b/runtime/vm/intermediate_language_x64.cc
@@ -968,9 +968,11 @@ Representation LoadIndexedInstr::representation() const {
     case kTypedDataUint16ArrayCid:
     case kOneByteStringCid:
     case kTwoByteStringCid:
+      return kTagged;
     case kTypedDataInt32ArrayCid:
+      return kUnboxedInt32;
     case kTypedDataUint32ArrayCid:
-      return kTagged;
+      return kUnboxedUint32;
     case kTypedDataFloat32ArrayCid:
     case kTypedDataFloat64ArrayCid:
       return kUnboxedDouble;
@@ -1052,6 +1054,29 @@ void LoadIndexedInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
     return;
   }
 
+  if ((representation() == kUnboxedUint32) ||
+      (representation() == kUnboxedInt32)) {
+    if ((index_scale() == 1) && index.IsRegister()) {
+      __ SmiUntag(index.reg());
+    }
+    Register result = locs()->out(0).reg();
+    switch (class_id()) {
+      case kTypedDataInt32ArrayCid:
+        ASSERT(representation() == kUnboxedInt32);
+        __ movsxd(result, element_address);
+        break;
+      case kTypedDataUint32ArrayCid:
+        ASSERT(representation() == kUnboxedUint32);
+        __ movl(result, element_address);
+        break;
+      default:
+        UNREACHABLE();
+    }
+    return;
+  }
+
+  ASSERT(representation() == kTagged);
+
   if ((index_scale() == 1) && index.IsRegister()) {
     __ SmiUntag(index.reg());
   }
@@ -1078,14 +1103,6 @@ void LoadIndexedInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
       __ movzxw(result, element_address);
       __ SmiTag(result);
       break;
-    case kTypedDataInt32ArrayCid:
-      __ movsxd(result, element_address);
-      __ SmiTag(result);
-      break;
-    case kTypedDataUint32ArrayCid:
-      __ movl(result, element_address);
-      __ SmiTag(result);
-      break;
     default:
       ASSERT((class_id() == kArrayCid) || (class_id() == kImmutableArrayCid));
       __ movq(result, element_address);