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6.7 Optimization

GNU Pascal is a 32/64 bit compiler with excellent optimization algorithms (which are identically the same as those of GNU C). There are six optimization levels, specified by the command line options `-O', `-O2', ..., `-O6'.

One example:

 
program OptimizationDemo;

procedure Foo; var A, B: Integer; begin A := 3; B := 4; WriteLn (A + B) end;

begin Foo end.

When GNU Pascal compiles this program with optimization (`-O3'), it recognizes that the argument to `WriteLn' is the constant 7 -- and optimizes away the variables A and B. If the variables were global, they would not be optimized away because they might be accessed from other places, but the constant 7 would still be optimized.

For more about optimization, see the GNU C documentation.



This document was generated by Frank Heckenbach on May, 10 2002 using texi2html