tree-inline.c (inlinable_function_p): Improve heuristics by using a smoother function to cut down allowable inlinable...

        * tree-inline.c (inlinable_function_p): Improve heuristics
        by using a smoother function to cut down allowable inlinable size.
        * param.def: Add parameters max-inline-insns-single,
        max-inline-slope, min-inline-insns that determine the exact
        shape of the above function.
        * param.h: Likewise.

From-SVN: r52832