On Mon, May 12, 2025 at 3:56 AM Richard Biener
<richard.guent...@gmail.com> wrote:
>
> On Sat, May 10, 2025 at 3:13 AM Andrew Pinski <quic_apin...@quicinc.com>
> wrote:
> >
> > This move this canonicalization from forwprop
> > (forward_propagate_into_gimple_cond)
> > to gimple-fold.
> > This is a step in removing forward_propagate_into_gimple_cond from forwprop.
>
> I don't think fold_stmt should mess with the CFG, so NACK.
I had that suspicion too.
> The code has to
> stay in forwprop, possibly it's also sth for CFG cleanup
> cleanup_control_expr_graph
> where we convert single-case switch () to if ().
CFG cleanup definitely seems like a good place for this.
Thanks,
Andrew
>
> > Bootstrapped and tested on x86_64-linux-gnu.
> >
> > gcc/ChangeLog:
> >
> > * gimple-fold.cc (replace_stmt_with_simplification): Canonicalize
> > `_Bool == 0` and `_Bool != 1` into `_Bool != 0` with swapping
> > the edges.
> >
> > Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
> > ---
> > gcc/gimple-fold.cc | 19 ++++++++++++++++++-
> > 1 file changed, 18 insertions(+), 1 deletion(-)
> >
> > diff --git a/gcc/gimple-fold.cc b/gcc/gimple-fold.cc
> > index c3a9f6356d4..e6d1384c416 100644
> > --- a/gcc/gimple-fold.cc
> > +++ b/gcc/gimple-fold.cc
> > @@ -6079,7 +6079,24 @@ replace_stmt_with_simplification
> > (gimple_stmt_iterator *gsi,
> > {
> > gcc_assert (res_op->code.is_tree_code ());
> > auto code = tree_code (res_op->code);
> > - if (TREE_CODE_CLASS (code) == tcc_comparison
> > + /* Canonicalize _Bool == 0 and _Bool != 1 to _Bool != 0 by swapping
> > edges. */
> > + if ((TREE_CODE (TREE_TYPE (ops[0])) == BOOLEAN_TYPE
> > + || (INTEGRAL_TYPE_P (TREE_TYPE (ops[0]))
> > + && TYPE_PRECISION (TREE_TYPE (ops[0])) == 1))
> > + && ((code == EQ_EXPR
> > + && integer_zerop (ops[1]))
> > + || (code == NE_EXPR
> > + && integer_onep (ops[1])))
> > + && gimple_bb (stmt))
> > + {
> > + basic_block bb = gimple_bb (stmt);
> > + gimple_cond_set_code (cond_stmt, NE_EXPR);
> > + gimple_cond_set_lhs (cond_stmt, ops[0]);
> > + gimple_cond_set_rhs (cond_stmt, build_zero_cst (TREE_TYPE
> > (ops[0])));
> > + EDGE_SUCC (bb, 0)->flags ^= (EDGE_TRUE_VALUE|EDGE_FALSE_VALUE);
> > + EDGE_SUCC (bb, 1)->flags ^= (EDGE_TRUE_VALUE|EDGE_FALSE_VALUE);
> > + }
> > + else if (TREE_CODE_CLASS (code) == tcc_comparison
> > /* GIMPLE_CONDs condition may not throw. */
> > && (!flag_exceptions
> > || !cfun->can_throw_non_call_exceptions
> > --
> > 2.43.0
> >
