Where does GCC pick passes for different opt. levels

[Marc Glisse]

On Mon, 11 Aug 2014, Steve Ellcey  wrote:

> I have a basic question about optimization selection in GCC.  There used to
> be some code in GCC (passes.c?) that would set various optimize pass flags
> depending on if the 'optimize' flag was > 0, > 1, or > 2; later I think
> there may have been a table.

There is still a table in opts.c, with entries that look like:

     { OPT_LEVELS_2_PLUS, OPT_ftree_vrp, NULL, 1 },


> This code seems gone now and I can't figure
> out how GCC is selecting what optimization passes to run at what optimization
> levels (-O1 vs. -O2 vs. -O3).  How is this handled in the top-of-tree GCC code?
>
> I see passes.def but there doesn't seem to be anything in there to tie
> specific passes to specific optimization levels.  Likewise in common.opt
> I see flags for various optimization passes but nothing to tie them to
> -O1 or -O2, etc.
>
> I'm probably missing something obvious, but a pointer would be much
> appreciated.

-- 
Marc Glisse