On Sat, 15 Oct 2016 22:50:11 +0000, Robert Prins wrote:
>
>Programs compiled with different optimization levels (and sometimes even other
>compiler options) are not the same program! Period. Full stop. End of story!
>
Many possibilities. A race condition might be won by the wrong path when
optimized; the desired path when not optimized. But beware of processor
upgrades.
I once had a program in a little-known langage from a vendor other than IBM
which program checked when optimized; at the debug levei it operated as I
had intended. Reported. Vendor replied (correctly) that I had (unwittingly)
used a construct clearly documented as undefined; unpredictable; NAPWAD.
(Not timing-dependent nor resource constrained.) I seethed that the object
of debugging mode is to report as many or more errors, not fewer. Vendor
remained adamant. it had been:
STH Removed ...
LH ... when optmized.
SLA ..,3 Fixed point overflow when optimized
-- gil
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