Allow looser heap accesses historically emitted by Emscripten.

test/mjsunit/wasm/asm-wasm.js

 // Copyright 2015 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.
 
 // Flags: --expose-wasm
 
 function EmptyTest() {
   "use asm";
   function caller() {
     empty();
@@ skipping 1152 matching lines @@
     valueOf: function() { return 99; }
   };
   TestCase({foo: o, bar: o, baz: o}, 99, 99, 99, 99);
   // Check that function values are converted properly.
   TestCase({foo: TestCase, bar: TestCase, qux: TestCase}, 0, NaN, 0, NaN);
   // Check that a missing ffi object is safe.
   TestCase(undefined, 0, NaN, 0, NaN);
 }
 
 TestForeignVariables();
+
+
+(function() {
+  function TestByteHeapAccessCompat(stdlib, foreign, buffer) {
+    "use asm";
+
+    var HEAP8 = new stdlib.Uint8Array(buffer);
+    var HEAP32 = new stdlib.Int32Array(buffer);
+
+    function store(i, v) {
+      i = i | 0;
+      v = v | 0;
+      HEAP32[i >> 2] = v;
+    }
+
+    function storeb(i, v) {
+      i = i | 0;
+      v = v | 0;
+      HEAP8[i | 0] = v;
+    }
+
+    function load(i) {
+      i = i | 0;
+      return HEAP8[i] | 0;
+    }
+
+    function iload(i) {
+      i = i | 0;
+      return HEAP8[HEAP32[i >> 2] | 0] | 0;
+    }
+
+    return {load: load, iload: iload, store: store, storeb: storeb};
+  }
+
+  var m = _WASMEXP_.instantiateModuleFromAsm(
+      TestByteHeapAccessCompat.toString());
+  m.store(0, 20);
+  m.store(4, 21);
+  m.store(8, 22);
+  m.storeb(20, 123);
+  m.storeb(21, 42);
+  m.storeb(22, 77);
+  assertEquals(123, m.load(20));
+  assertEquals(42, m.load(21));
+  assertEquals(77, m.load(22));
+  assertEquals(123, m.iload(0));
+  assertEquals(42, m.iload(4));
+  assertEquals(77, m.iload(8));
+})();