Some questions about the C -Optimiser

bj at yale-com.UUCP bj at yale-com.UUCP
Tue Jun 14 06:23:55 AEST 1983


    (This  is  a  reply  to mckusic's (sp?)  answer about not optimizing r0
    references.)  Suggestion:    change  the  optimizer  to  go  ahead  and
    optimize  if  the  r0  instructions  are  followed by anything except a
    'ret'.  The C compiler will only generate an r0 instruction  that  also
    includes the return value before a return(e), correct?

This could cause problems in cases like
	return ( e ? a = b+1 : c = d+1 )

This problem is caused because the optimizer only has the code, it does
not know the intent of statements.  This is also the reason that device
driver code can not be optimized.
						B.J.



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