[Bug middle-end/61577] [4.9.0 Regression] can't compile on hp-ux v3 ia64

["me at larbob dot org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61577

--- Comment #249 from Larkin Nickle <me at larbob dot org> ---
I am still unable to replicate a proper 11.1 build against 2.36 gas. Here's my
process:

HP GCC 4.7.1 -> GCC 4.7.4:

../../sources/gcc-4.7.4/configure --prefix=/usr/util/toolchain/gcc-4.7.4 --w
ith-as=/opt/hp-gcc/bin/as --enable-languages=c,c++ --disable-nls

-> 4.9.2:

../../sources/gcc-4.9.2/configure --disable-libgomp --with-as=/opt/hp-gcc/bi
n/as --enable-languages=c,c++ --prefix=/usr/util/toolchain/gcc-4.9.2
--disable-n
ls

Then, I compiled binutils 2.36 (w/ -mlp64), gmp 6.2.1, mpfr 4.1.0, and mpc
1.2.1 with HP GCC 4.7.1. All GMP tests passed except for `t-printf`, all mpfr
tests passed except `tasprintf`, and all mpc tests passed. These results are
the same as John's except his `t-printf` passes with GMP.

Then, I compile GCC 11.1.0 with GCC 4.9.2:

../../sources/gcc-11.1.0/configure --prefix=/usr/util/toolchain/gcc-11.1.0 -
-enable-comdat --disable-libgomp --disable-nls
--with-as=/usr/util/toolchain/bin
utils-2.36/bin/as --with-gmp=/usr/util/toolchain/gmp-6.2.1
--with-mpfr=/usr/util
/toolchain/mpfr-4.1.0 --with-mpc=/usr/util/toolchain/mpc-1.2.1
--enable-language
s=c,c++ --with-dwarf2

First it errors out when compiling charset.c:

../../../sources/gcc-11.1.0-new/libcpp/charset.c: In function 'cset_converter
init_iconv_desc(cpp_reader*, const char*, const char*)':
../../../sources/gcc-11.1.0-new/libcpp/charset.c:695:1: internal compiler
error: in plus_constant, at explow.c:101
  695 | }
      | ^
libbacktrace could not find executable to open 

Then, if libcpp's Makefile is patched so that charset.c is built with -O1, I
eventually run into other errors:

../../../../sources/gcc-11.1.0-new/libgcc/libgcov-interface.c: In function
'gcov_clear':
../../../../sources/gcc-11.1.0-new/libgcc/libgcov-interface.c:143:1: internal
compiler error: Illegal instruction
  143 | }
      | ^
libbacktrace could not find executable to open 

After making that compile with -O1:

../../../sources/gcc-11.1.0/zlib/inftrees.c: In function 'inflate_table':
../../../sources/gcc-11.1.0/zlib/inftrees.c:32:19: internal compiler error:
Illegal instruction
   32 | int ZLIB_INTERNAL inflate_table(type, lens, codes, table, bits, work)
      |                   ^~~~~~~~~~~~~
libbacktrace could not find executable to open

I am only able to get a build of 11.1 with BOOT_CFLAGS="-g -O1"
BOOT_CXXFLAGS="-g -O1".

It's worth noting that I have rebuilt gmp with the -O1'd 11.1 build and it
fixed the `t-printf` test not passing. I then rebuilt mpfr and mpc against it
with 4.7.1 (4.9.2 and 11.1 can't seem to properly compile mpfr) and then tried
to build 11.1 against the new builds and still ran into the same issues.