It would be interesting to see how this rule ("x = (y + c1) + c2 => x = y + (с1 + с2)") was encoded in the compiler. I guess it has more complicated form than a (simple and declarative) term rewriting rule, which you may use on AST transform stage.
There is a quote from Muchnik's textbook: "Like constant folding, algebraic simplifications and reassociation are best structured in a compiler as a subroutine that can be called from any other phase that can make use of it".
But it seems that in some cases, on the later phases with lower IRs, you just can't use this "subroutine" as is.
Thank you, really interesting reading!
It would be interesting to see how this rule ("x = (y + c1) + c2 => x = y + (с1 + с2)") was encoded in the compiler. I guess it has more complicated form than a (simple and declarative) term rewriting rule, which you may use on AST transform stage.
There is a quote from Muchnik's textbook: "Like constant folding, algebraic simplifications and reassociation are best structured in a compiler as a subroutine that can be called from any other phase that can make use of it".
But it seems that in some cases, on the later phases with lower IRs, you just can't use this "subroutine" as is.