On Thu, 2 Jun 2022, Jakub Jelinek wrote:
> On Thu, Jun 02, 2022 at 08:36:42AM +0000, Richard Biener wrote:
> > > --- gcc/match.pd.jj 2022-06-01 13:54:32.000654151 +0200
> > > +++ gcc/match.pd 2022-06-01 15:13:35.473084402 +0200
> > > @@ -5969,6 +5969,17 @@ (define_operator_list SYNC_FETCH_AND_AND
> > > && (!TYPE_UNSIGNED (TREE_TYPE (@2)) || TYPE_UNSIGNED (TREE_TYPE
> > > (@0))))
> > > (ovf @1 @0))))
> > >
> > > +/* Optimize __builtin_mul_overflow_p (x, cst, (utype) 0) if all 3 types
> > > + are unsigned to x > (umax / cst). */
> > > +(simplify
> > > + (imagpart (IFN_MUL_OVERFLOW:cs@2 @0 integer_nonzerop@1))
> >
> > does :c work here? I think it is at least ignored, possibly diagnostic
> > in genmatch is missing ...
>
> I saw it used in another pattern, so thought it will work fine:
> (cmp:c (realpart (IFN_ADD_OVERFLOW:c@2 @0 @1)) @0)
>
> And looking at the generated source, I think it does work:
> case CFN_MUL_OVERFLOW:
> if (gimple_call_num_args (_c1) == 2)
> {
> tree _q20 = gimple_call_arg (_c1, 0);
> _q20 = do_valueize (valueize, _q20);
> tree _q21 = gimple_call_arg (_c1, 1);
> _q21 = do_valueize (valueize, _q21);
> if (integer_nonzerop (_q21))
> {
> {
> /* #line 5976 "../../gcc/match.pd" */
> tree captures[3] ATTRIBUTE_UNUSED = { _p0, _q20,
> _q21 };
> if (gimple_simplify_256 (res_op, seq, valueize,
> type, captures))
> return true;
> }
> }
> if (integer_nonzerop (_q20))
> {
> {
> /* #line 5976 "../../gcc/match.pd" */
> tree captures[3] ATTRIBUTE_UNUSED = { _p0, _q21,
> _q20 };
> if (gimple_simplify_256 (res_op, seq, valueize,
> type, captures))
> return true;
> }
> }
> }
> Though, sure, I should test it in the testcase too.
Ah yeah, we simply trust :c on functions with two arguments (and
explicitely handle CFN_FMA).
Richard.
