Add support for parsing csret

llvm-svn: 28406
diff --git a/llvm/lib/AsmParser/Lexer.l b/llvm/lib/AsmParser/Lexer.l
index f930609..dc94cca 100644
--- a/llvm/lib/AsmParser/Lexer.l
+++ b/llvm/lib/AsmParser/Lexer.l
@@ -218,6 +218,7 @@
 
 cc              { return CC_TOK; }
 ccc             { return CCC_TOK; }
+csretcc         { return CSRETCC_TOK; }
 fastcc          { return FASTCC_TOK; }
 coldcc          { return COLDCC_TOK; }