Using GCC without the GNU assembler
Marcel Moolenaar reports
The 3 different assemblers that I know of do differ in subtle and sometimes hugely annoying and incompatible ways. The default output of GCC cannot be handled by the Intel assembler, nor the HP-UX assembler (both for different reasons). Versions data: GCC 3.3.3 Intel assembler v8.0U and v9.0U (beta) HP-UX assembler B.11.23
Thus, as this stage, you can not build GCC on IA64 with anything but the GNU assembler.