On Wednesday, 6 August 2014 at 07:29:02 UTC, Ola Fosheim Grøstad
wrote:
On Wednesday, 6 August 2014 at 06:56:40 UTC, eles wrote:
Not right:
b = a+1
assume(b>C)
implies
assume(a+1>C)
b = a+1
b = a+1
if(C<=b) exit(1);
implies
if(C<=a+1) exit(1);
b = a+1
Is not the same? Still, one would allow the optimizer to exit
before executing b=a+1 line (in the first version) based on that
condition (considering no volatile variables).
I stick to my point: as long as the code is there, optimization
based on it is acceptable (as long as the functionality of the
program is not changed, of course). The sole floating point is
what to do when the code that is used for optimization is
discarded.
Would you accept optimization of a C program based on code that
is guarded by:
#ifndef _NDEBUG
//code that could be used for optimization
#endif
in the -D_NDEBUG version?
(I am not convinced 100% that for D is the same, but should help
with the concepts)
