Fix LoadOptimizer's handling of load/stores with constant indices for TypedData.

tests/language/vm/load_to_load_forwarding_vm_test.dart

 // Copyright (c) 2012, 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.
 // Test correctness of side effects tracking used by load to load forwarding.
 
 // VMOptions=--optimization-counter-threshold=10
 
 import "package:expect/expect.dart";
 import "dart:typed_data";
 
@@ skipping 468 matching lines @@
 
 testAliasesRefinement() {
   zz = new ZZ();
   var b = zz;
   if (b.f == null) {
     b.f = f0;
   }
   return b.f;
 }
 
+testViewAliasing1() {
+  final f64 = new Float64List(1);
+  final f32 = new Float32List.view(f64.buffer);
+  f64[0] = 1.0;  // lower 32bits are all 0s

[Florian Schneider, 2015/01/26 13:30:39]

Comment: Should not be forwarded.

[Vyacheslav Egorov (Google), 2015/01/26 14:57:16]

Done.

+  f32[1] = 2.0;  // upper 32bits for 2.0f and 2.0 are the same
+  return f64[0];
+}
+
+testViewAliasing2() {
+  final f64 = new Float64List(2);
+  final f64v = new Float64List.view(f64.buffer, Float64List.BYTES_PER_ELEMENT);
+  f64[1] = 1.0;

[Florian Schneider, 2015/01/26 13:30:39]

Comment: Should be forwarded.

[Vyacheslav Egorov (Google), 2015/01/26 14:57:16]

Should *not* be forwarded.

+  f64v[0] = 2.0;
+  return f64[1];
+}
+
+testViewAliasing3() {
+  final u8 = new Uint8List(Float64List.BYTES_PER_ELEMENT * 2);
+  final f64 = new Float64List.view(u8.buffer, Float64List.BYTES_PER_ELEMENT);
+  f64[0] = 1.0;

[Florian Schneider, 2015/01/26 13:30:39]

Comment: Should be forwarded, [0,7] and [14], [15] don't overlap.

[Vyacheslav Egorov (Google), 2015/01/26 14:57:16]

note: view starts at 8 - means f64[0] is bytes 8-15. should not be forwarded.

+  u8[15] = 0x40;
+  u8[14] = 0x00;
+  return f64[0];
+}
+
+testViewAliasing4() {
+  final u8 = new Uint8List(Float64List.BYTES_PER_ELEMENT * 2);
+  final f64 = new Float64List.view(u8.buffer, Float64List.BYTES_PER_ELEMENT);
+  f64[0] = 2.0;  // Not aliased: should be forwarded.

[Florian Schneider, 2015/01/26 13:30:39]

This should not be forwarded, since f64[0] writes [0,7] and [0],[1] overlap.

[Vyacheslav Egorov (Google), 2015/01/26 14:57:16]

note: view starts at 8 like about. should *be* forwarded.

+  u8[0] = 0x40;
+  u8[1] = 0x00;
+  return f64[0];
+}
+
 main() {
   final fixed = new List(10);
   final growable = [];
   testImmutableVMFields(fixed, true);
   testImmutableVMFields(growable, false);
   testImmutableVMFields(growable, false);
 
   final f64List = new Float64List(2);
   testPhiRepresentation(true, f64List);
   testPhiRepresentation(false, f64List);
@@ skipping 46 matching lines @@
   for (var i = 0; i < 20; i++) {
     Expect.equals(3, testIndexedNoAlias(array));
   }
 
   testIndexedAliasedStores();
 
   var test_array = new List(1);
   for (var i = 0; i < 20; i++) {
     Expect.equals(43, testAliasingStoreIndexed(global_array));
   }
+
+  for (var i = 0; i < 20; i++) {
+    Expect.equals(2.0, testViewAliasing1());
+    Expect.equals(2.0, testViewAliasing2());
+    Expect.equals(2.0, testViewAliasing3());
+    Expect.equals(2.0, testViewAliasing4());
+  }
 }