Quote Originally Posted by Sly
As Paulius said, all three approaches produced the same assembly code, so they are all the same speed.
IIRC on Turbo Pascal succ() and pred() were faster, just like with TP

x:=x+1;

was slower than inc(x);

So people using succ and pred instead of +1 and -1 probably have this habit from TP times.

FPC and Delphi optimize this away, and succ and pred are now typically only useful for enumerations.