Allow the INREG parameter attribute to be added to functions. This permits the

function result to be passed in a register. This implements the GCC regparm
function attribute for llvm by translation to the InReg parameter attribute 
and fixes test/CFrontend/2002-07-30-SubregSetAssertion.c

llvm-svn: 40619

llvm/lib/AsmParser/llvmAsmParser.y

@@ -1245,6 +1245,7 @@ FuncAttr      : NORETURN { $$ = ParamAttr::NoReturn; }
               | NOUNWIND { $$ = ParamAttr::NoUnwind; }
               | ZEROEXT  { $$ = ParamAttr::ZExt;     }
               | SIGNEXT  { $$ = ParamAttr::SExt;     }
+              | INREG    { $$ = ParamAttr::InReg;    }
               ;
 
 OptFuncAttrs  : /* empty */ { $$ = ParamAttr::None; }