https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97832
--- Comment #23 from Hongtao.liu <crazylht at gmail dot com> ---
> the blends do not look like no-ops so I wonder if this is really computing
> the same thing ... (it swaps lane 0 from the two loads from x but not the
> stores)
They're computing the same thing since we also do the same "permutation" for
the invariants: f_re and f_imm, can we eliminate that in the vectorizer?
_232 = {f_im_36, f_im_36, f_im_36, f_im_36};
_231 = {f_im_36, f_re_35, f_re_35, f_re_35}; ------- here
_216 = {f_re_35, f_re_35, f_re_35, f_re_35};
_215 = {f_re_35, f_im_36, f_im_36, f_im_36}; ------ and here.
ivtmp.36_221 = (unsigned long) y_41(D);
ivtmp.38_61 = (unsigned long) x_33(D);
<bb 4> [local count: 214748368]:
# ivtmp.32_66 = PHI <ivtmp.32_65(4), 0(3)>
# ivtmp.36_64 = PHI <ivtmp.36_63(4), ivtmp.36_221(3)>
# ivtmp.38_220 = PHI <ivtmp.38_60(4), ivtmp.38_61(3)>
# DEBUG c => NULL
# DEBUG k => 0
# DEBUG BEGIN_STMT
# DEBUG BEGIN_STMT
# DEBUG D#78 => D#79 * 8
# DEBUG D#77 => x_33(D) + D#78
_62 = (void *) ivtmp.38_220;
vect_x_im_61.13_228 = MEM <const vector(4) double> [(const double *)_62];
vect_x_im_61.14_226 = MEM <const vector(4) double> [(const double *)_62 +
32B];
vect_x_re_55.15_225 = VEC_PERM_EXPR <vect_x_im_61.14_226,
vect_x_im_61.13_228, { 0, 5, 6, 7 }>;
vect_x_re_55.23_209 = VEC_PERM_EXPR <vect_x_im_61.13_228,
vect_x_im_61.14_226, { 0, 5, 6, 7 }>;
# DEBUG D#76 => *D#77
# DEBUG x_re => D#76
# DEBUG BEGIN_STMT
# DEBUG D#74 => (long unsigned int) D#75
# DEBUG D#73 => D#74 * 8
# DEBUG D#72 => x_33(D) + D#73
# DEBUG D#71 => *D#72
# DEBUG x_im => D#71
# DEBUG BEGIN_STMT
# DEBUG D#70 => y_41(D) + D#78
_59 = (void *) ivtmp.36_64;
vect_y_re_63.9_235 = MEM <vector(4) double> [(double *)_59];
vect_y_re_63.10_233 = MEM <vector(4) double> [(double *)_59 + 32B];
vect__42.18_219 = .FMA (vect_x_im_61.13_228, _232, vect_y_re_63.10_233);
vect_y_re_69.17_222 = .FNMA (vect_x_re_55.15_225, _231, vect_y_re_63.9_235);
vect_y_re_69.25_206 = .FNMA (vect_x_re_55.23_209, _215, vect_y_re_69.17_222);
vect_y_re_69.25_205 = .FNMA (_216, vect_x_im_61.14_226, vect__42.18_219);
