https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111401
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
Last reconfirmed| |2023-09-13
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
The vectorizer sees if-converted code like
<bb 3> [local count: 955630224]:
# init_20 = PHI <_36(8), init_12(D)(18)>
# i_22 = PHI <i_18(8), 0(18)>
_1 = (long unsigned int) i_22;
_2 = _1 * 4;
_3 = cond_15(D) + _2;
_4 = *_3;
_23 = _4 != 0;
_6 = _1 * 8;
_38 = _37 + _6;
_7 = (double *) _38;
_8 = .MASK_LOAD (_7, 64B, _23);
_ifc__35 = _23 ? _8 : 0.0;
_36 = init_20 + _ifc__35;
i_18 = i_22 + 1;
if (n_13(D) > i_18)
so what it produces matches up here. There's the possibility to
modify the if-conversion handling to use a COND_ADD instead of
the COND_EXPR plus ADD, I think that would be the best thing here.
See tree-if-conv.cc:is_cond_scalar_reduction/convert_scalar_cond_reduction
I think this is also wrong code when signed zeros are involved.
