IA64 inline division question

[Steve Ellcey <sje at cup dot hp dot com>]

I have been experimenting with doing inlined floating point division on
IA64 instead of using __divsf3, etc.  The HP compiler does this at all
optimization levels and it should result in a performance improvement at
the cost of a slightly larger object size.

Currently when trying to run SPEC with inlined floating point division,
if I do no optimization I get the correct results, if I combine it with
-O2 then 177.mesa fails with incorrect results.  I suspect, but am not
sure, that some incorrect instruction scheduling might be happening.

Currently I am looking at two issues that seem suspicious to me, one is
that *recip_approx (and *sqrt_approx) are defined as the itanium_class
fmisc.  I am wondering if this is correct or if they should be fmac
instead.  Or perhaps they need their own type.  The other issue is with
the attribute itanium_requires_unit0.  This treats fmac and fmisc
differently but I don't see where it is used.  Is itanium_requires_unit0
obsolete?

I am going to try and create a small test case but in the mean time I
thought I would see if anyone has any ideas on what the problem might be
or had any suggestions on what else I should be looking at.

Steve Ellcey
sje@cup.hp.com