A64: When truncating to an int, store the result in a 64bit register

test/cctest/test-assembler-a64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 9334 matching lines @@
   TEARDOWN();
 }
 
 
 static void ECMA262ToInt32Helper(int32_t expected, double input) {
   SETUP();
   START();
 
   __ Fmov(d0, input);
 
-  __ ECMA262ToInt32(x0, d0, x10, x11, MacroAssembler::INT32_IN_W);
-  __ ECMA262ToInt32(x1, d0, x10, x11, MacroAssembler::INT32_IN_X);
+  __ ECMA262ToInt32(x1, d0, x10, x11, MacroAssembler::INT32);
   __ ECMA262ToInt32(x2, d0, x10, x11, MacroAssembler::SMI);
 
-  // The upper bits of INT32_IN_W are undefined, so make sure we don't try to
-  // test them.
-  __ Mov(w0, w0);
-
   END();
 
   RUN();
 
   int64_t expected64 = expected;
 
-  ASSERT_EQUAL_32(expected, w0);
   ASSERT_EQUAL_64(expected64, x1);
   ASSERT_EQUAL_64(expected64 << kSmiShift | kSmiTag, x2);
 
   TEARDOWN();
 }
 
 
 TEST(ecma_262_to_int32) {
   INIT_V8();
   // ==== exponent < 64 ====
@@ skipping 186 matching lines @@
   AbsHelperX(-42);
   AbsHelperX(kXMinInt);
   AbsHelperX(kXMaxInt);
 
   AbsHelperW(0);
   AbsHelperW(42);
   AbsHelperW(-42);
   AbsHelperW(kWMinInt);
   AbsHelperW(kWMaxInt);
 }