Added test cases for truncating stores.

Review URL: https://codereview.chromium.org/741643003

Cr-Commit-Position: refs/heads/master@{#25474}

test/mjsunit/compiler/truncating-store.js

+// Copyright 2014 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.
+
+var asm = (function Module(global, env, buffer) {
+  "use asm";
+
+  var i8 = new global.Int8Array(buffer);
+  var u8 = new global.Uint8Array(buffer);
+  var i16 = new global.Int16Array(buffer);
+  var u16 = new global.Uint16Array(buffer);
+  var i32 = new global.Int32Array(buffer);
+  var u32 = new global.Uint32Array(buffer);
+
+  var H = 0;
+
+  function store_i8() {
+    H = 4294967295;
+    i8[0 >> 0]= H;
+    return i8[0 >> 0];
+  }
+
+  function store_u8() {
+    H = 4294967295;
+    u8[0 >> 0]= H;
+    return u8[0 >> 0];
+  }
+
+  function store_i16() {
+    H = 4294967295;
+    i16[0 >> 0]= H;
+    return i16[0 >> 0];
+  }
+
+  function store_u16() {
+    H = 4294967295;
+    u16[0 >> 0]= H;
+    return u16[0 >> 0];
+  }
+
+  function store_i32() {
+    H = 4294967295;
+    i32[0 >> 0]= H;
+    return i32[0 >> 0];
+  }
+
+  function store_u32() {
+    H = 4294967295;
+    u32[0 >> 0]= H;
+    return u32[0 >> 0];
+  }
+
+  return { store_i8: store_i8,
+           store_u8: store_u8,
+           store_i16: store_i16,
+           store_u16: store_u16,
+           store_i32: store_i32,
+           store_u32: store_u32 };
+})({
+  "Int8Array": Int8Array,
+  "Uint8Array": Uint8Array,
+  "Int16Array": Int16Array,
+  "Uint16Array": Uint16Array,
+  "Int32Array": Int32Array,
+  "Uint32Array": Uint32Array
+}, {}, new ArrayBuffer(64 * 1024));
+
+assertEquals(-1, asm.store_i8());
+assertEquals(255, asm.store_u8());
+assertEquals(-1, asm.store_i16());
+assertEquals(65535, asm.store_u16());
+assertEquals(-1, asm.store_i32());
+assertEquals(4294967295, asm.store_u32());

test/mjsunit/mjsunit.status

@@ -54,6 +54,9 @@
   ##############################################################################
   # TurboFan compiler failures.
 
+  # TODO(jarin) We should truncate instead of change for some stores.
+  'compiler/truncating-store': [PASS, FAIL],
+
   # TODO(mstarzinger): An arguments object materialized in the prologue can't
   # be accessed indirectly. Either we drop that requirement or wait for support
   # from the deoptimizer to do that.