next up previous
Next: Expression evaluation with mixed Up: Simplification or optimization Previous: Equality

Strength reduction

Do compilers still change

for i from 1 to n do
   z= i*x
  ...
end
to
 z=0;
for i from 1 to n do
  z=z+x
  ..
end ??
This provides an opportunity for n rounding errors instead of one. This kind of reduction works quite well for integer operations.



Richard J. Fateman
Thu Aug 13 13:55:33 PDT 1998