Re: Possible CSE quirk involving SUBREG on the i386

["David S. Miller" <davem at dm dot cobaltmicro dot com>]

   Date: Tue, 30 Jun 1998 22:00:09 -0600
   From: Jeffrey A Law <law@hurl.cygnus.com>

   Yup.  Combine looks at insns in groups of 2 or 3.

   You can make it look at larger groups by making intermediate patterns.

   Here's an example from the H8 port:

Ok, that would work, neat trick :-)

However, it is really a workaround for the core problem.
But, I'm concerned that increasing the number of patterns combine
looks at in one go will increase compile time considerably.

The next question arises as to what a good number would be, perhaps
the code in combine can be made generic enough that a target header
define can tell it the max number of patterns to ever try to coalesce
at once?

Later,
David S. Miller
davem@dm.cobaltmicro.com