strength reduction and other optimizations

["Bill McEnaney" <bill at rkirkpat dot net>]

Hi, Everybody,

Various people disagree about whether I should multiply by a reciprocal
when I could do a floating point division instead.  Others tell me that
it's best to let the compiler replace integer division by a power of two
with a right shift.  If I do either optimization by hand, will that
prevent the compiler from noticing other optimizations it could do? 
I've read somewhere that I should let C compilers do the optimizations
I've described.  Is that true about gcc's C compiler?  Is it bet for me
to trust it to do optimizations I could do?

Thanks.

Bill
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