Paul McGuire wrote:
> Does Python's run-time do any optimization of multiplication
> operations, like it does for boolean short-cutting? That is, for a
> product a*b, is there any shortcutting of (potentially expensive)
> multiplication operations
no. and the reason is very simple: to the extent such optimization
makes sense, it has been done on assembler/CPU level already. i.e. when
the multiplication is mapped to the machine code
IMUL <op>
the Pentium processor would be smart enough not to do the work if AX or
the op are 0 or 1.
Python has no job trying to outsmart Intel (and the other chipmakers).
Boolean shortcuts are useful for entirely different reason, not speed.
e.g.
if lastDigit == 0 or i % lastDigit != 0:
break
if both operands of OR were to be evaluated, that would end up with
division-by-zero exception for lastDigit=0.
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