Current egcs, binutils and kernel (fwd)

[Gabriel Paubert]

On Tue, 20 Apr 1999, David Edelsohn wrote:

> 	The purpose of my earlier message was to explain what was
> occurring in rs6000.md and why GCC was calling the function instead of
> inlining the code.  I thought that some people might actually want to
> understand *WHY* the function was required and why GCC was behaving as
> designed. 

Ok, calm down. But I still don't know why GCC does not expand this inline. 
It's 8 or 10 instructions, without branches so it's not much bigger than a
call for which you have to set up 3 parameter registers and which may
destroy many more registers according to the ABI conventions.
Furthermore if only one of the 2 result registers is needed, it may be
simplified quite significantly (i'm not sure it's easy to do in current
GCC to split a variable using 2 registers to remove dead code).

Maybe it's time to add the alternatives in rs6000.md, enabled with a
-minline-longlongshifts option. But I don't yet know enough of GCC to 
implement it.

	Gabriel. 


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