It's a general view that a faster code will consume less power because you can put CPU in idle state for more time but when we talk about energy consumption, is following a possibility:
Suppose there's a instruction sequence which gets executed in 1ms and during the execution process the average current consumption was say 40mA . .and your Vdd is 3.3V
so total energy consumed = V*I*t = 3.3 * 40*10^-3 * 1*10^-3 Joules = 13.2*10^-6 Joules
and in another case there's a instruction sequence which gets executed in 2ms and during execution process the average current consumption is 15mA . .and Vdd is 3.3V
so total energey consumed = V*I*t = 3.3 * 15*10^-3 * 2*10^-3 Joules = 9.9*10^-6 Joules
so the question comes to. .. . Is there any architecture which has different instruction sets for performing the same task with different current consumptions?
And if there are ...then is there any compiler which takes this into account and generates a code which is energy efficient?