Added repe_cmpsw instruction to x86, x86_64 assemblers

Change-Id: I7634959eebb64d607f47497db320d5c2afdef16b
diff --git a/compiler/utils/x86/assembler_x86_test.cc b/compiler/utils/x86/assembler_x86_test.cc
index aacc57b..0e8c4ae 100644
--- a/compiler/utils/x86/assembler_x86_test.cc
+++ b/compiler/utils/x86/assembler_x86_test.cc
@@ -196,4 +196,10 @@
   DriverStr(expected, "Repnescasw");
 }
 
+TEST_F(AssemblerX86Test, Repecmpsw) {
+  GetAssembler()->repe_cmpsw();
+  const char* expected = "repe cmpsw\n";
+  DriverStr(expected, "Repecmpsw");
+}
+
 }  // namespace art