Added repe_cmpsw instruction to x86, x86_64 assemblers

Change-Id: I7634959eebb64d607f47497db320d5c2afdef16b
diff --git a/compiler/utils/x86_64/assembler_x86_64.h b/compiler/utils/x86_64/assembler_x86_64.h
index 61ffeab..0cd3197 100644
--- a/compiler/utils/x86_64/assembler_x86_64.h
+++ b/compiler/utils/x86_64/assembler_x86_64.h
@@ -603,6 +603,7 @@
   void bswapq(CpuRegister dst);
 
   void repne_scasw();
+  void repe_cmpsw();
 
   //
   // Macros for High-level operations.