VM: Support phis with pair representations.

runtime/vm/intermediate_language_mips.cc

 // Copyright (c) 2013, 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.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_MIPS.
 #if defined(TARGET_ARCH_MIPS)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/dart_entry.h"
@@ skipping 4913 matching lines @@
     const int32_t shift =
         reinterpret_cast<int32_t>(locs()->in(1).constant().raw()) >> 1;
     switch (op_kind()) {
       case Token::kSHR: {
         if (shift < 32) {
           __ sll(out_lo, left_hi, 32 - shift);
           __ srl(TMP, left_lo, shift);
           __ or_(out_lo, out_lo, TMP);
           __ sra(out_hi, left_hi, shift);
         } else {
-          __ sra(out_lo, left_hi, shift - 32);
+          if (shift == 32) {
+            __ mov(out_lo, left_hi);
+          } else if (shift < 64) {
+            __ sra(out_lo, left_hi, shift - 32);
+          } else {
+            __ sra(out_lo, left_hi, 31);
+          }
           __ sra(out_hi, left_hi, 31);
         }
         break;
       }
       case Token::kSHL: {
+        ASSERT(shift < 64);
         if (shift < 32) {
           __ srl(out_hi, left_lo, 32 - shift);
           __ sll(TMP, left_hi, shift);
           __ or_(out_hi, out_hi, TMP);
           __ sll(out_lo, left_lo, shift);
         } else {
           __ sll(out_hi, left_lo, shift - 32);
           __ mov(out_lo, ZR);
         }
         // Check for overflow.
@@ skipping 646 matching lines @@
                                 1,
                                 locs());
   __ lw(result, Address(SP, 1 * kWordSize));
   __ addiu(SP, SP, Immediate(2 * kWordSize));
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS