Problem in split_basic_block

[Richard Kenner]

    addp4 does a 32-bit add and then copies the 2 most significant bits of
    the 32-bit result (31 and 30) into the 2 most significant bits of the
    target register (63 and 62).  This gives you access to 4 segments
    (regions).

Right, I know that.

    You really should have some understanding of the IA-64 ISA if you are 
    trying to do a port.

I'm not the person most involved in the port, just the one that's
working on this particular bug.  The people doing the port certainly have
that documentation.

    See Vol 2 Section 4.1.9 32-bit Virtual Addressing.  This documents how 
    to do zero-extend, sign-extend, or pointer-swizzling addressing via 
    addp4.  All 3 are supported by the architecture.

OK, then there's indeed no efficiency issue after all.  Good.  HP obviously
gets to choose which one they want to use for VMS.