C common practice. (what it really is)

Jim Giles jlg at cochiti.lanl.gov
Tue Apr 30 02:19:10 AEST 1991


In article <1991Apr27.024634.586 at convex.com>, grogers at convex.com (Geoffrey Rogers) writes:
|> In article <TMB.91Apr26145719 at volterra.ai.mit.edu> tmb at ai.mit.edu (Thomas M. Breuel) writes:
|> >compile, and, with most compilers, you inhibit all global optimization.
|> 	       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^	
|> Huh???? What do you mean by global optimization? Most texts on optimization
|> consider global optimization to be between basic blocks within a procdure.
|> Having one function per source file does not inhibit this. Everything
|> else that you said is true/good common sense.

As uncharacteristic as it is for me to defend people that I disagree
with, it is legitimate to refer to the use of IM analysis to improve
optimization of global data and procedure arguments as 'global 
optimization'.  Is is also true that in the field of compiler 
construction, the term is use exclusively to mean optimization
of all code _within_ a given compilation unit but _across_ basic
block boundaries.  The language is (unfortunately) used both ways
in the programming community as a whole.  Nothing you can do about
it but grin and bear it.

J. Giles



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