Re:C Is Not a Low-level Language (2018)
by vnorilo on Tuesday December 28, 2021 @04:06PM
(#29718179)
You'd be surprised how stable it actually is in practice. The occasional big swings in benchmarks tend to be due to compiler A pattern-matching an idiom that compiler B does not. Regressions from A.1 to A.2 are rare, and usually either bugs or that optimizer default target has shifted and now neglects whatever uarch you regressed on.
But this may change from compiler to compiler and from version to version of the same compiler. I think you may be better off writing assembly code directly rather than trying to coerce the compiler to do exactly what you want.