On Tue, Nov 3, 2020 at 2:35 PM Jakub Jelinek <ja...@redhat.com> wrote: > > On Tue, Nov 03, 2020 at 02:27:52PM +0100, Richard Biener wrote: > > On Fri, Oct 23, 2020 at 1:47 PM Martin Liška <mli...@suse.cz> wrote: > > > This is a follow-up of the discussion that happened in thread about > > > no_stack_protector > > > attribute: https://gcc.gnu.org/pipermail/gcc-patches/2020-May/545916.html > > > > > > The current optimize attribute works in the following way: > > > - 1) we take current global_options as base > > > - 2) maybe_default_options is called for the currently selected > > > optimization level, which > > > means all rules in default_options_table are executed > > > - 3) attribute values are applied (via decode_options) > > > > > > So the step 2) is problematic: in case of -O2 -fno-omit-frame-pointer and > > > __attribute__((optimize("-fno-stack-protector"))) > > > ends basically with -O2 -fno-stack-protector because > > > -fno-omit-frame-pointer is default: > > > /* -O1 and -Og optimizations. */ > > > { OPT_LEVELS_1_PLUS, OPT_fomit_frame_pointer, NULL, 1 }, > > > > > > My patch handled and the current optimize attribute really behaves that > > > same as appending attribute value > > > to the command line. So far so good. We should also reflect that in > > > documentation entry which is quite > > > vague right now: > > > > > > """ > > > The optimize attribute is used to specify that a function is to be > > > compiled with different optimization options than specified on the > > > command line. > > > """ > > > > > > and we may want to handle -Ox in the attribute in a special way. I guess > > > many macro/pragma users expect that > > > > > > -O2 -ftree-vectorize and __attribute__((optimize(1))) will end with -O1 > > > and not > > > with -ftree-vectorize -O1 ? > > > > Hmm. I guess the only two reasonable options are to append to the active > > set > > and thus end up with -ftree-vectorize -O1 or to start from an empty set and > > thus > > end up with -O1. > > I'd say we always want to append, but only take into account explicit > options. > So basically get the effect of > take the command line, append to that options from the optimize/target > pragmas in effect and append to that options from optimize/target > attributes and only from that figure out the implicit options.
OK, so minus target options that is what martins patch does, right? Richard. > Jakub >
