On Tue, May 28, 2019 at 1:57 AM Jakub Jelinek <ja...@redhat.com> wrote:
>
> On Sat, Feb 16, 2019 at 07:02:11AM -0800, H.J. Lu wrote:
> > > For NOTE_INSN_DELETED_LABEL, we should check if forced_labels to see
> > > if its address is taken. Also ix86_init_large_pic_reg shouldn't set
> > > LABEL_PRESERVE_P (in_struct) since NOTE_INSN_DELETED_LABEL is suffcient
> > > to keep the label.
>
> Can you explain when is it ever needed to emit ENDBR on
> NOTE_INSN_DELETED_LABEL? Only labels that are proven not to be ever
> branched to are turned into deleted labels, so I think the right answer is
> never emit any ENDBR on those...
>
This condition is checked by gcc.target/i386/cet-label-5.c in the
patch. For
void *
func (void)
{
return &&bar;
bar:
return 0;
}
we generate:
(note/s 4 2 10 2 ("bar") NOTE_INSN_DELETED_LABEL 2)
(insn:TI 10 4 11 2 (set (reg/i:DI 0 ax)
(label_ref:DI [4 deleted]))
"/export/gnu/import/git/gitlab/x86-gcc/gcc/testsuite/gcc.target/i386/cet-label-5.c":13:1
66 {*movdi_internal}
(nil))
(insn 11 10 20 2 (use (reg/i:DI 0 ax))
"/export/gnu/import/git/gitlab/x86-gcc/gcc/testsuite/gcc.target/i386/cet-label-5.c":13:1
-1
(nil))
--
H.J.
