Managed to build gmp-5.0.1, mpfr-2.4.2, and mpc-0.8.1 with gcc-4.2.4/64 (all -mlp64). Had to set $ABI to 64 to make that pass.
Due to the endless annoying libtool, building with HP C-ANSI-C was impossible. With that triplet installed, and hand-forced iconv to be unavailable (--disable-nls does not disable it's use and configure seems to think it is there where it is not), I had to handcompile version.c because of quotation errors. Those are all things I can work around, but here it stops: /pro/3gl/GNU/gcc/obj/./gcc/xgcc -B/pro/3gl/GNU/gcc/obj/./gcc/ -B/usr/local/ia64/ia64-hp-hpux11.31/bin/ -B/usr/local/ia64/ia64-hp-hpux11.31/lib/ -isystem /usr/local/ia64/ia64-hp-hpux11.31/include -isystem /usr/local/ia64/ia64-hp-hpux11.31/sys-include -g -mlp64 -fPIC -mlp64 -O2 -g -mlp64 -fPIC -DIN_GCC -DUSE_LIBUNWIND_EXCEPTIONS -W -Wall -Wwrite-strings -Wcast-qual -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition -isystem ./include -g -DHAVE_GTHR_DEFAULT -DIN_LIBGCC2 -D__GCC_FLOAT_NOT_NEEDED -I. -I. -I../../.././gcc -I../../../../src/libgcc -I../../../../src/libgcc/. -I../../../../src/libgcc/../gcc -I../../../../src/libgcc/../include -DHAVE_CC_TLS -o _popcountsi2.o -MT _popcountsi2.o -MD -MP -MF _popcountsi2.dep -DL_popcountsi2 -c ../../../../src/libgcc/../gcc/libgcc2.c \ ../../../../src/libgcc/../gcc/libgcc2.c: In function '__popcountdi2': ../../../../src/libgcc/../gcc/libgcc2.c:795:1: internal compiler error: Segmentation fault Please submit a full bug report, with preprocessed source if appropriate. It's your own source, so I don't think I have to include it. (Even HP's porting center gave up after gcc-4.2.3) -- Summary: Impossible to build any version beyond 4.2.4 Product: gcc Version: 4.5.0 Status: UNCONFIRMED Severity: blocker Priority: P3 Component: bootstrap AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: h dot m dot brand at xs4all dot nl GCC build triplet: ia64-hp-hpux11.31 GCC host triplet: ia64-hp-hpux11.31 GCC target triplet: ia64-hp-hpux11.31 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43941