On Sun, Nov 3, 2024 at 11:23 PM Lewis Hyatt <lhy...@gmail.com> wrote: > > While testing 64-bit location_t support, I ran into an -fcompare-debug issue > that was traced back here. Despite the name, next_discriminator_for_locus() > is meant to take an integer line number argument, not a location_t. There is > one call site which has been passing a location_t instead. For the most part > that is harmless, although in case there are two CALL stmts on the same line > with different location_t, it may fail to generate a unique discriminator > where it should. Once location_t is configured to be 64-bit, however, it > produces an -fcompare-debug failure which is what I noticed. Fix it by passing > the line number rather than the location_t. > > I am not aware of a testcase that demonstrates any observable wrong > behavior, but the file debug/pr53466.C is an example where the discriminator > assignment is indeed different before and after this change.
OK. (also for affected branches) Thanks, Richard. > gcc/ChangeLog: > > * tree-cfg.cc (assign_discriminators): Fix incorrect value passed to > next_discriminator_for_locus(). > --- > gcc/tree-cfg.cc | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/gcc/tree-cfg.cc b/gcc/tree-cfg.cc > index 3eede0d61cd..c2100a51a7a 100644 > --- a/gcc/tree-cfg.cc > +++ b/gcc/tree-cfg.cc > @@ -1251,7 +1251,7 @@ assign_discriminators (void) > } > /* Allocate a new discriminator for CALL stmt. */ > if (gimple_code (stmt) == GIMPLE_CALL) > - curr_discr = next_discriminator_for_locus (curr_locus); > + curr_discr = next_discriminator_for_locus (curr_locus_e.line); > } > > gimple *last = last_nondebug_stmt (bb);
