Re: [PATCH 1/5] Fix asymmetric comparison functions

[Andrey Belevantsev <abel at ispras dot ru>]

On 17.12.2015 15:13, Yury Gribov wrote:
> On 12/17/2015 02:58 PM, Andrey Belevantsev wrote:
> > Hello,
> >
> > On 17.12.2015 11:58, Yury Gribov wrote:
> > > Some obvious symmetry fixes.
> > >
> > > Cc-ing
> > > * Andrey (Belevantsev) for bb_top_order_comparator
> >
> > Here, as Jakub mentioned, we assume that the argument addresses will
> > never be equal,
>
> The problem is that this is not guaranteed.

Well, if the consensus is that this is indeed the case, you're free to 
change both places as you suggest.

Yours,
Andrey

> > thus that would always be different basic blocks (the
> > comparator is used for providing a custom sort over loop body bbs) and
> > you don't need a return 0 there.  You can put there gcc_unreachable
> > instead as in ...
> >
> > > * Andrew (MacLeod) for compare_case_labels
> > > * Andrew (Pinski) for resort_field_decl_cmp
> > > * Diego for pair_cmp
> > > * Geoff for resort_method_name_cmp
> > > * Jakub for compare_case_labels
> > > * Jason for method_name_cmp
> > > * Richard for insert_phi_nodes_compare_var_infos, compare_case_labels
> > > * Steven for cmp_v_in_regset_pool
> >
> > ... this case -- here gcc_unreachable () marks that we're sorting pool
> > pointers and their values are always different.  Please do not remove it.
>
> Same here.
>
> /Yury