C optimizer bug?

[jeff%aids-unix at sri-unix.UUCP]

From:  Jeff Dean <jeff at aids-unix>

Brian,

I've found a solution to your problem, where
	CVTDL	a,b
	BICL	$-256,c
	MOVL	c,d

was being optimized (sic) to
	MOVZBL	a,d

However, not being a "c2 guru", and finding the comments in c2
somewhat lacking, I'm afraid that my fix might be only "local"
solution (i.e., I only know that it solves this particular
problem).  However, if anyone fails to come up with a better
solution, I'll be glad to make mine available (it's only two new
lines of code for c21.c).  

	jd

P.S.  This is for 4.1
TS DONE UNDER
4.2 COULD BE ASSURED TO RUN UNDER SYSTEM 5?  THANKS IN ADVANCE, ED FOX.