On Sat, Apr 28, 2012 at 4:48 PM, Alexander Monakov <amona...@ispras.ru> wrote: > > Looks like people who want to play with optimization options are still tripped > by the fact that optimizations are not enabled unless -O is given (even though > it's documented in the manual now). Can we add a warning for that like below? > > Untested beside bubblestrap. I suppose this will produce noise for -O0 > torture testsuite — what is the recommended way to fix that? > > diff --git a/gcc/opts-common.c b/gcc/opts-common.c > index 354bce0..a18a89d 100644 > --- a/gcc/opts-common.c > +++ b/gcc/opts-common.c > @@ -1056,6 +1056,11 @@ read_cmdline_option (struct gcc_options *opts, > if (!handle_option (opts, opts_set, decoded, lang_mask, DK_UNSPECIFIED, > loc, handlers, false, dc)) > error_at (loc, "unrecognized command line option %qs", opt); > + > + if ((option->flags & CL_OPTIMIZATION)
That's surely too coarse - you will warn about options that _will_ have an effect. There is currently no easy way to glob all affected options. I don't think we want to warn about -O2 -ftree-pre -O0 either, nor about -fno-tree-pre. Overall I would expect people to have noticed that with -O0 these options have no effect when they've gone all the way to figure out the separate optimization options, no? Thanks, Richard. > + && !opts->x_optimize) > + warning_at (loc, 0, "optimization option %qs has no effect " > + "at zero -O level", opt); > } > > /* Set any field in OPTS, and OPTS_SET if not NULL, for option
