Re^2: Oh noooooo!!

Walter Bright bright at Data-IO.COM
Tue Oct 3 05:17:50 AEST 1989


In article <1989Sep30.172817.17852 at ux1.cso.uiuc.edu> mcdonald at aries.scs.uiuc.edu (Doug McDonald) writes:
<If data-flow analysis is made difficult by goto-s, why should be any different
<for a program restructured, probably by use of 
<flag variables.

Data-flow analysis is not made difficult by goto's. Simple and powerful
algorithms exist to deal with them.

Replacing goto-s with flag variables makes it very difficult to optimize,
and I know of no optimizer that is able to convert them into equivalent
goto's.

P.S. My optimizer works by initially converting whiles, fors, dos, etc.
into goto's! The internal structure is a graph of expressions connected
by goto's. All memory of high level constructs is lost. Graph analysis is
used to determine loops and such.



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