The documentation in rtl.texi for the HIGH and LO_SUM operators incorrectly say that they should use Pmode. There is no such restriction. They can be used with any mode. Pmode is only necessary if the operand is an address, such as a SYMBOL_REF or a LABEL_REF. The text will need some rewording to make this clear.
-- Summary: incorrect documentat for high and lo_sum RTL operators Product: gcc Version: 4.1.0 Status: UNCONFIRMED Severity: normal Priority: P2 Component: other AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: wilson at gcc dot gnu dot org CC: gcc-bugs at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21110