[Bug inline-asm/49142] New: Invalid 8bit register operand

["hjl.tools at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49142

           Summary: Invalid 8bit register operand
           Product: gcc
           Version: 4.6.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: inline-asm
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: hjl.tools@gmail.com
            Target: x86_64


i386.md has

(define_insn "*movqi_extzv_2_rex64"
  [(set (match_operand:QI 0 "register_operand" "=Q,?R")
        (subreg:QI
          (zero_extract:SI (match_operand 1 "ext_register_operand" "Q,Q")
                           (const_int 8)
                           (const_int 8)) 0))]
  "TARGET_64BIT"
{
  switch (get_attr_type (insn))
    {
    case TYPE_IMOVX:
      return "movz{bl|x}\t{%h1, %k0|%k0, %h1}";
    default:
      return "mov{b}\t{%h1, %0|%0, %h1}";
    }
}

However, since %ah can only be used with legacy 8bit register,
it puts restriction on the other operand.  We shouldn't generate
"movb %ah, %dil".