Landing: MIPS: Fixed a bug in a special case of MacroAssembler::Ext.

src/mips/macro-assembler-mips.cc

 // Copyright 2011 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 747 matching lines @@
                          uint16_t size) {
   ASSERT(pos < 32);
   ASSERT(pos + size < 33);
 
   if (mips32r2) {
     ext_(rt, rs, pos, size);
   } else {
     // Move rs to rt and shift it left then right to get the
     // desired bitfield on the right side and zeroes on the left.
     int shift_left = 32 - (pos + size);
-    if (shift_left > 0) {
-      sll(rt, rs, shift_left);
-    }
+    sll(rt, rs, shift_left);  // Acts as a move if shift_left == 0.
 
     int shift_right = 32 - size;
     if (shift_right > 0) {
       srl(rt, rt, shift_right);
     }
   }
 }
 
 
 void MacroAssembler::Ins(Register rt,
@@ skipping 3516 matching lines @@
        opcode == BGTZL);
   opcode = (cond == eq) ? BEQ : BNE;
   instr = (instr & ~kOpcodeMask) | opcode;
   masm_.emit(instr);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS