Evidently it's high time for me to try out v4.8.1 against the FBSL sources. Perhaps I'll be able to enjoy a 30% boost there too.
I actually did succeed in compiling FBSL v3.5 RC2 with GCC v4.8.1 and it did add a 10% to 15% boost to all my integer and floating-point benchmarks, respectively. But:
1. The size of Fbsl.exe binary has increased by 110KB from its current 606KB to 716KB.
2. GCC's new SEH scheme interferes with my own SEH implementation and doesn't work quite like I want it to. Nor am I able to either disable or override this new feature altogether.
3. The new data and code section layout within the binaries generated by GCC v4.8.1 require that I rewrite my elaborate hand-coded FBSL executable compilation routine from scratch. I'd rather not spend two more weeks of my time recoding and debugging it again.
That said, I guess FBSL v3.5 will stay as it is even if it makes it run somewhat slower than I'd like it to. That's my final decision.