He gets different results with and without optimization because
without optimization the result of the calculation is spilled
to the i unsigned int and then reloaded for the print call.
This save and reload truncated the value to its real value. In
the optimized version, the compiler removed the spill and the
overflowed value contained in the register is printed as is.
Btw you are actually confirming what I said.
if (i != 0xFFFFFFFF) ...
In the optimized version, when the 64 bits "i" value is compared
to a 32 bits constant, the test fails...
Proof that the value is stored in a **64** bits register, not
32...
