Sharing hard registers

[Alan Lehotsky]

At 4:27 PM -0600 6/13/02, law@redhat.com wrote:
>In message <200206132203.g5DM3lv24315@potter.sfbay.redhat.com>, 
>"Eric Christoph
>er" writes:
>  > On Thu, 13 Jun 2002 13:27:39 -0700, law wrote:
>  >
>  >
>  > > It may be necessary to back out the last patch which makes gen_rtx_REG
>  > > share hard registers in some circumstances.
>  > >

	The porting guide's "Structure Sharing Assumptions" needs to 
be updated to
	explicitly indicate that hard registers are "shared".  Right 
now, it just says
	that pseudos are always shared.

	Also, I'm curious about the issue of a hard-register with 
more than one mode.
	How does that work if R1 can be a SF or a SI mode value???

	Doesn't the mode get in the way of sharing the hard register? 
Or is this cached
	by (mode,regno).?

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