An intermediate step: adding -qhot suboptions at level 3

At -O3, the optimization includes minimal -qhot loop transformations at level=0 to increase performance. You can further increase your performance benefit by increasing the level and therefore the aggressiveness of -qhot. Try specifying -qhot without any suboptions, or -qhot=level=1.

For more information on -qhot, see Using high-order loop analysis and transformations.