[Bug target/63679] [5.0 Regression][AArch64] Failure to constant fold.

[belagod at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63679

--- Comment #2 from Tejas Belagod <belagod at gcc dot gnu.org> ---
foo.c.optimized:

5.0:

;;    prev block 0, next block 1, flags: (NEW, REACHABLE)
;;    pred:       ENTRY [100.0%]  (FALLTHRU,EXECUTABLE)
  # .MEM_4 = VDEF <.MEM_3(D)>
  aD.1380 = *.LC0D.1387;
  # VUSE <.MEM_4>
  vect__6.6_13 = MEM[(intD.7 *)&aD.1380];
  # VUSE <.MEM_4>
  vect__6.6_10 = MEM[(intD.7 *)&aD.1380 + 16B];
  _27 = BIT_FIELD_REF <vect__6.6_13, 32, 0>;
  _16 = BIT_FIELD_REF <vect__6.6_10, 32, 0>;
  _15 = _16 + _27;
  _18 = BIT_FIELD_REF <vect__6.6_13, 32, 32>;
  _14 = BIT_FIELD_REF <vect__6.6_10, 32, 32>;
  _5 = _14 + _18;
  _12 = BIT_FIELD_REF <vect__6.6_13, 32, 64>;
  _2 = BIT_FIELD_REF <vect__6.6_10, 32, 64>;
  _29 = _2 + _12;
  _30 = BIT_FIELD_REF <vect__6.6_13, 32, 96>;
  _31 = BIT_FIELD_REF <vect__6.6_10, 32, 96>;
  _32 = _30 + _31;
  vect_sum_7.7_17 = {_15, _5, _29, _32};
  stmp_sum_7.8_19 = _15;
  stmp_sum_7.8_20 = _5;
  stmp_sum_7.8_21 = stmp_sum_7.8_19 + stmp_sum_7.8_20;
  stmp_sum_7.8_22 = _29;
  stmp_sum_7.8_23 = stmp_sum_7.8_21 + _29;
  stmp_sum_7.8_24 = _32;
  stmp_sum_7.8_25 = stmp_sum_7.8_23 + _32;
  vect_sum_7.9_26 = stmp_sum_7.8_25;
  # .MEM_9 = VDEF <.MEM_4>
  aD.1380 ={v} {CLOBBER};
  # VUSE <.MEM_9>
  return vect_sum_7.9_26;
;;    succ:       EXIT [100.0%] 


Very strange that vectorizer seems to be kicking in with -mgeneral-regs-only

4.9.2:

;;   basic block 2, loop depth 0, count 0, freq 1111, maybe hot
;;    prev block 0, next block 1, flags: (NEW, REACHABLE)
;;    pred:       ENTRY [100.0%]  (FALLTHRU,EXECUTABLE)
  # .MEM_4 = VDEF <.MEM_3(D)>
  aD.1374[0] = 0;
  # .MEM_5 = VDEF <.MEM_4>
  aD.1374[1] = 1;
  # .MEM_6 = VDEF <.MEM_5>
  aD.1374[2] = 2;
  # .MEM_7 = VDEF <.MEM_6>
  aD.1374[3] = 3;
  # .MEM_8 = VDEF <.MEM_7>
  aD.1374[4] = 4;
  # .MEM_9 = VDEF <.MEM_8>
  aD.1374[5] = 5;
  # .MEM_10 = VDEF <.MEM_9>
  aD.1374[6] = 6;
  # VUSE <.MEM_10>
  _20 = aD.1374[0];
  # VUSE <.MEM_10>
  _29 = aD.1374[1];
  sum_30 = _20 + _29;
  # VUSE <.MEM_10>
  _36 = aD.1374[2];
  sum_37 = sum_30 + _36;
  # VUSE <.MEM_10>
  _43 = aD.1374[3];
  sum_44 = sum_37 + _43;
  # VUSE <.MEM_10>
  _50 = aD.1374[4];
  sum_51 = sum_44 + _50;
  # VUSE <.MEM_10>
  _57 = aD.1374[5];
  sum_58 = sum_51 + _57;
  # VUSE <.MEM_10>
  _64 = aD.1374[6];
  sum_65 = sum_58 + _64;
  sum_14 = sum_65 + 7;
  # .MEM_17 = VDEF <.MEM_10>
  aD.1374 ={v} {CLOBBER};
  # VUSE <.MEM_17>
  return sum_14;
;;    succ:       EXIT [100.0%] 

4.9's much saner.