GCC build failed with your patch on 2001-01-09T11:35:00Z.

[Geoff Keating]

> Date: Tue, 9 Jan 2001 13:58:07 -0800
> From: Richard Henderson <rth@redhat.com>

> The correctness issue is that with a 32-bit H_W_I we cannot do 128-bit
> arithmetic in the compiler.  Since bitsizetype is TImode for a 64-bit
> target, cross-compiling from a 32-bit H_W_I does not work.  This has
> been broken ever since bitsizetype was introduced.

I think this code makes it work (from set_sizetype):

  int precision = MIN (oprecision + BITS_PER_UNIT_LOG + 1,
                       2 * HOST_BITS_PER_WIDE_INT);

so if HOST_BITS_PER_WIDE_INT is 32, the precision of bitsizetype is
limited to 64.  This is perfectly OK for AIX-64 as the machine's
memory map can't deal with a 2^61-byte contiguous region anyway.

-- 
- Geoffrey Keating <geoffk@geoffk.org>