On Sun, May 19, 2024 at 8:37 AM <pan2...@intel.com> wrote: > > From: Pan Li <pan2...@intel.com> > > This patch would like to support the branchless form for unsigned > SAT_ADD when leverage __builtin_add_overflow. For example as below: > > uint64_t sat_add_u(uint64_t x, uint64_t y) > { > uint64_t ret; > uint64_t overflow = __builtin_add_overflow (x, y, &ret); > > return (T)(-overflow) | ret; > } > > Before this patch: > > uint64_t sat_add_u (uint64_t x, uint64_t y) > { > long unsigned int _1; > long unsigned int _2; > long unsigned int _3; > __complex__ long unsigned int _6; > uint64_t _8; > > ;; basic block 2, loop depth 0 > ;; pred: ENTRY > _6 = .ADD_OVERFLOW (x_4(D), y_5(D)); > _1 = REALPART_EXPR <_6>; > _2 = IMAGPART_EXPR <_6>; > _3 = -_2; > _8 = _1 | _3; > return _8; > ;; succ: EXIT > > } > > After this patch: > > uint64_t sat_add_u (uint64_t x, uint64_t y) > { > uint64_t _8; > > ;; basic block 2, loop depth 0 > ;; pred: ENTRY > _8 = .SAT_ADD (x_4(D), y_5(D)); [tail call] > return _8; > ;; succ: EXIT > > } > > The below tests suite are passed for this patch. > * The rv64gcv fully regression test. > * The x86 bootstrap test. > * The x86 fully regression test. > > gcc/ChangeLog: > > * match.pd: Add SAT_ADD right part 2 for __builtin_add_overflow. > > Signed-off-by: Pan Li <pan2...@intel.com> > --- > gcc/match.pd | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/gcc/match.pd b/gcc/match.pd > index b291e34bbe4..5328e846aff 100644 > --- a/gcc/match.pd > +++ b/gcc/match.pd > @@ -3064,6 +3064,10 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) > (negate (convert (ne (imagpart (IFN_ADD_OVERFLOW:c @0 @1)) integer_zerop))) > (if (TYPE_UNSIGNED (type) && integer_types_ternary_match (type, @0, @1)))) > > +(match (usadd_right_part_2 @0 @1) > + (negate (imagpart (IFN_ADD_OVERFLOW:c @0 @1))) > + (if (TYPE_UNSIGNED (type) && integer_types_ternary_match (type, @0, @1)))) > +
Can you merge this with the patch that makes use of the usadd_right_part_2 match? It's difficult to review on its own. > /* We cannot merge or overload usadd_left_part_1 and usadd_left_part_2 > because the sub part of left_part_2 cannot work with right_part_1. > For example, left_part_2 pattern focus one .ADD_OVERFLOW but the > -- > 2.34.1 >