VM: Support phis with pair representations.

runtime/vm/intermediate_language_ia32.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_IA32.
 #if defined(TARGET_ARCH_IA32)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/dart_entry.h"
@@ skipping 6070 matching lines @@
     // Code for a constant shift amount.
     ASSERT(locs()->in(1).constant().IsSmi());
     const int32_t shift =
         reinterpret_cast<int32_t>(locs()->in(1).constant().raw()) >> 1;
     switch (op_kind()) {
       case Token::kSHR: {
         if (shift > 31) {
           __ movl(left_lo, left_hi);  // Shift by 32.
           __ sarl(left_hi, Immediate(31));  // Sign extend left hi.
           if (shift > 32) {
-            __ sarl(left_lo, Immediate(shift - 32));
+            __ sarl(left_lo, Immediate(shift > 63 ? 31 : shift - 32));
           }
         } else {
           __ shrdl(left_lo, left_hi, Immediate(shift));
           __ sarl(left_hi, Immediate(shift));
         }
         break;
       }
       case Token::kSHL: {
         if (can_overflow()) {
           Register temp1 = locs()->temp(0).reg();
           Register temp2 = locs()->temp(1).reg();
           __ movl(temp1, left_hi);  // Preserve high 32 bits.
           if (shift > 31) {
             __ movl(left_hi, left_lo);  // Shift by 32.
             if (shift > 32) {
               __ shll(left_hi, Immediate(shift - 32));

[regis, 2015/10/06 17:37:24]

ditto

             }
             // Check for overflow by sign extending the high 32 bits
             // and comparing with the input.
             __ movl(temp2, left_hi);
             __ sarl(temp2, Immediate(31));
             __ cmpl(temp1, temp2);
             __ j(NOT_EQUAL, deopt);
             if (shift > 32) {
               // Also compare low word from input with high word from
               // output shifted back shift - 32.
               __ movl(temp2, left_hi);
               __ sarl(temp2, Immediate(shift - 32));

[regis, 2015/10/06 17:37:24]

ditto

               __ cmpl(left_lo, temp2);
               __ j(NOT_EQUAL, deopt);
             }
             __ xorl(left_lo, left_lo);  // Zero left_lo.
           } else {
             __ shldl(left_hi, left_lo, Immediate(shift));
             __ shll(left_lo, Immediate(shift));
             // Check for overflow by shifting back the high 32 bits
             // and comparing with the input.
             __ movl(temp2, left_hi);
             __ sarl(temp2, Immediate(shift));
             __ cmpl(temp1, temp2);
             __ j(NOT_EQUAL, deopt);
           }
         } else {
           if (shift > 31) {
             __ movl(left_hi, left_lo);  // Shift by 32.
             __ xorl(left_lo, left_lo);  // Zero left_lo.
             if (shift > 32) {
               __ shll(left_hi, Immediate(shift - 32));

[regis, 2015/10/06 17:37:24]

ditto

             }
           } else {
             __ shldl(left_hi, left_lo, Immediate(shift));
             __ shll(left_lo, Immediate(shift));
           }
         }
         break;
       }
       default:
         UNREACHABLE();
@@ skipping 721 matching lines @@
   __ Drop(1);
   __ popl(result);
 }
 
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_IA32