On Sun, Mar 13, 2022 at 02:03:33PM +0100, Eric Botcazou wrote:
> > Bootstrapped/regtested on {x86_64,i686,powerpc64le,aarch64,s390x}-linux,
> > ok for trunk?
> >
> > 2022-03-13 Jakub Jelinek <ja...@redhat.com>
> >
> > PR rtl-optimization/104814
> > * ifcvt.cc (find_if_case_1, find_if_case_2): Punt if test_bb
> > doesn't end with onlyjump_p.
> >
> > * gcc.c-torture/execute/pr104814.c: New test.
> >
> > --- gcc/ifcvt.cc.jj 2022-02-09 12:55:50.750773751 +0100
> > +++ gcc/ifcvt.cc 2022-03-11 17:30:44.248855063 +0100
> > @@ -5259,6 +5259,10 @@ find_if_case_1 (basic_block test_bb, edg
> > && CROSSING_JUMP_P (BB_END (else_bb))))
> > return FALSE;
> >
> > + /* Verify test_bb ends in a conditional jump with no other side-effects.
> > */ + if (!BB_END (test_bb) || !onlyjump_p (BB_END (test_bb)))
> > + return FALSE;
> > +
> > /* THEN has one successor. */
> > if (!single_succ_p (then_bb))
> > return FALSE;
> > @@ -5380,6 +5384,10 @@ find_if_case_2 (basic_block test_bb, edg
> > && CROSSING_JUMP_P (BB_END (else_bb))))
> > return FALSE;
> >
> > + /* Verify test_bb ends in a conditional jump with no other side-effects.
> > */ + if (!BB_END (test_bb) || !onlyjump_p (BB_END (test_bb)))
> > + return FALSE;
> > +
> > /* ELSE has one successor. */
> > if (!single_succ_p (else_bb))
> > return FALSE;
>
> Are the !BB_END tests really necessary? cond_exec_process_if_block has the
> same test on onlyjump_p without it. Likewise for noce_find_if_block.
Probably not, I've put it there only because the neighboring code is testing
it too:
if ((BB_END (then_bb)
&& JUMP_P (BB_END (then_bb))
&& CROSSING_JUMP_P (BB_END (then_bb)))
|| (BB_END (test_bb)
&& JUMP_P (BB_END (test_bb))
&& CROSSING_JUMP_P (BB_END (test_bb)))
|| (BB_END (else_bb)
&& JUMP_P (BB_END (else_bb))
&& CROSSING_JUMP_P (BB_END (else_bb))))
return FALSE;
find_if_header which calls find_if_case_* has:
if (EDGE_COUNT (test_bb->succs) != 2)
return NULL;
at the start, and I think an empty bb can't have more than one successor,
because there is nothing to cause different control flow.
Jakub
