MIPS: Fixed a bug in CopyBytes() and new test cases for MIPS macro assembler.

src/mips/macro-assembler-mips.cc

Index: src/mips/macro-assembler-mips.cc
diff --git a/src/mips/macro-assembler-mips.cc b/src/mips/macro-assembler-mips.cc
index 159c924b5bf044a442f23f0b1e8919581a076788..cbb538f39d34d8977c978fd08681f5dbce3b31a8 100644
--- a/src/mips/macro-assembler-mips.cc
+++ b/src/mips/macro-assembler-mips.cc
@@ -3220,11 +3220,10 @@ void MacroAssembler::CopyBytes(Register src,
                                Register dst,
                                Register length,
                                Register scratch) {
-  Label align_loop, align_loop_1, word_loop, byte_loop, byte_loop_1, done;
+  Label align_loop_1, word_loop, byte_loop, byte_loop_1, done;
 
   // Align src before copying in word size chunks.
-  bind(&align_loop);
-  Branch(&done, eq, length, Operand(zero_reg));
+  Branch(&byte_loop, le, length, Operand(kPointerSize));
   bind(&align_loop_1);
   And(scratch, src, kPointerSize - 1);
   Branch(&word_loop, eq, scratch, Operand(zero_reg));
@@ -3233,7 +3232,7 @@ void MacroAssembler::CopyBytes(Register src,
   sb(scratch, MemOperand(dst));
   Addu(dst, dst, 1);
   Subu(length, length, Operand(1));
-  Branch(&byte_loop_1, ne, length, Operand(zero_reg));
+  Branch(&align_loop_1, ne, length, Operand(zero_reg));
 
   // Copy bytes in word size chunks.
   bind(&word_loop);