Question

in compiler technology reduction in strength means closed

Answer 1

 strength reduction is a compiler optimization where expensive operations are replaced with equivalent but less expensive operations. 

Examples of strength reduction include:

• replacing a multiplication within a loop with an addition
• replacing an exponentiation within a loop with a multiplication

c = 7;
for (i = 0; i < N; i++)
{
    y[i] = c * i;
}

can be replaced with successive weaker additions

c = 7;
k = 0;
for (i = 0; i < N; i++)
{
    y[i] = k;
    k = k + c;
}