I've got a very simple c program which copies all elements from array A to
back to array A. For example,
int *A;
A = (int*)malloc(sizeof(int)*SIZE);
for( i = 0; i < SIZE; i++) {
A[i] = A[i];
}
I was expecting this to be optimised out by the compiler and eventually
turned into a noop. However, by measuring the runtime of this loop and
looking at the assembly code, it seems that the element is indeed loaded
from memory into register and then stored back to the same memory location.
I have -O3 enabled. Can anyone explain to me why the c compiler does not
optimise it? Or am I missing something here?
Many thanks.
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