On Tue, Nov 16, 2021 at 12:45 PM Jojo R via Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > Skip renaming if instruction is noop move, and it will > been removed for performance.
Is there any (target specific) testcase you can add? Such commits are problematic when later bisected to since the intent isn't clear. > gcc/ > * regrename.c (find_rename_reg): Return satisfied regno > if instruction is noop move. > --- > gcc/regrename.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/gcc/regrename.c b/gcc/regrename.c > index b8a9ca36f22..cb605f5176b 100644 > --- a/gcc/regrename.c > +++ b/gcc/regrename.c > @@ -394,6 +394,9 @@ find_rename_reg (du_head_p this_head, enum reg_class > super_class, > this_head, *unavailable)) > return this_head->tied_chain->regno; > > + if (noop_move_p (this_head->first->insn)) > + return best_new_reg; > + > /* If PREFERRED_CLASS is not NO_REGS, we iterate in the first pass > over registers that belong to PREFERRED_CLASS and try to find the > best register within the class. If that failed, we iterate in > -- > 2.24.3 (Apple Git-128) >
