2.95, x86: severe performance problems with short arithmetic

[Richard Henderson]

On Tue, Aug 10, 1999 at 11:00:53PM -0600, Jeffrey A Law wrote:
> Instead we need to do more analysis to determine when it is profitable to
> promote from 8/16 bit operations to 32bit operations.

The new_ia32_branch currently just disables all such promotions when
TARGET_PARTIAL_REG_STALL.  Not ideal, perhaps, but much better than
blindly going ahead with the promotions.

Yes, a post-reload pass to match up register usage modes would be the
ideal solution, but something like that isn't going to go into 2.95.1.

IMO going through the 10 to 20 patterns in the existing code base 
that do such promotions and conditionally disabling them is the only
viable course for 2.95.



r~