Is it legal for a C++ optimizer to reorder calls to clock()?

Question

The C++ Programming Language 4th edition, page 225 reads: A compiler may reorder code to improve performance as long as the result is identical to that of the s

Answer 1

Let's suppose that the sequence is in a loop, and the veryLongComputation () randomly throws an exception. Then how many t0s and t1s will be calculated? Does it pre-calculate the random variables and reorder based on the precalculation - sometimes reordering and sometimes not?

Is the compiler smart enough to know that just a memory read is a read from shared memory. The read is a measure of how far the control rods have moved in a nuclear reactor. The clock calls are used to control the speed at which they are moved.

Or maybe the timing is controlling the grinding of a Hubble telescope mirror. LOL

Moving clock calls around seems too dangerous to leave to the decisions of compiler writers. So if it is legal, perhaps the standard is flawed.

IMO.