gcc/config/score/score.md:113ff:

{
  switch (which_alternative)
    {
    case 0: return mdp_limm (operands);
    case 1: return mdp_move (operands);
    case 2: return mdp_linsn (operands, MDA_BYTE, false);
    case 3: return mdp_sinsn (operands, MDA_BYTE);
    case 4: return TARGET_MAC ? \"mf%1%S0 %0\" : \"mf%1    %0\";   <--------
    case 5: return TARGET_MAC ? \"mt%0%S1 %1\" : \"mt%0    %1\";   <--------
    case 6: return \"mfsr    %0, %1\";                             <--------
    case 7: return \"mtsr    %1, %0\";                             <--------
    default: gcc_unreachable ();
    }
}

This is in a brace block, NOT in a double quote string. These escapes are
bogus.

This is revision 127595.