Programming languages, imperative ones in particular, place a lot of emphasis on sequence. Take this simple pseuodocode for example:

components = [4.5, 3.2, 4.0, 3.8]
min(round_down(components))

The result of this code is 3, but that same result can very clearly be achieved in a less computationally expensive manner by performing:

round_down(min(components))

Correct me if I am wrong, but current day compilers operate on source code that lacks the semantic to perform such an optimization.