Do you realize that this is open source and being offered to you as a gift? The license allows you to compile this tool with whatever compiler and flags you want. Please do that if you care about the optimizations. But please do not post dismissive comments when someone is putting themselves in a vulnerable position willingly by sharing their hard work for free with the community. If you have feedback to offer, do it constructively with kindness and acceptance, not with reproach and snide.
Project Dev here, if you'd be willing to help me with that part I would be greatful. When I talk about "fast" I mean all searches are O(1) due to the magic of hash maps.
Fast FTS use reverse indices with trigrams, not primitive hash maps.
Any links to papers or docs about that? Interested.