[Bug tree-optimization/105216] [12 regression] 8% regression for m-queens compared to gcc11 O2 on CLX.

[crazylht at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105216

--- Comment #6 from Hongtao.liu <crazylht at gmail dot com> ---
(In reply to Hongtao.liu from comment #5)
> My bisect shows it's caused by
> r12-3876-g4a960d548b7d7d942f316c5295f6d849b74214f5

pre dump before vs after

-    goto <bb 21>; [11.00%]
-
-  <bb 12> [local count: 105119324]:
-  pretmp_379 = cols[d_243]; ---- miss optimization here.
-
-  <bb 13> [local count: 955630226]:
-  # level4_cnt_250 = PHI <level4_cnt_236(20), level4_cnt_242(12)>
-  # d_252 = PHI <d_98(20), d_243(12)>
-  # posib_254 = PHI <posib_102(20), posib_244(12)>
-  # diagl_shifted_255 = PHI <diagl_shifted_103(20), diagl_shifted_184(12)>
-  # diagr_shifted_256 = PHI <diagr_shifted_104(20), diagr_shifted_185(12)>
-  # l_rest_257 = PHI <l_rest_115(20), prephitmp_366(12)>
-  # prephitmp_380 = PHI <prephitmp_378(20), pretmp_379(12)>
+    goto <bb 19>; [11.00%]
+
+  <bb 12> [local count: 955630226]:
+  # level4_cnt_250 = PHI <level4_cnt_205(18), level4_cnt_242(11)>
+  # d_252 = PHI <d_47(18), d_243(11)>
+  # posib_254 = PHI <posib_27(18), posib_244(11)>
+  # diagl_shifted_255 = PHI <diagl_shifted_25(18), diagl_shifted_184(11)>
+  # diagr_shifted_256 = PHI <diagr_shifted_24(18), diagr_shifted_185(11)>
+  # l_rest_257 = PHI <l_rest_13(18), prephitmp_313(11)>
   _30 = ~posib_254;
   _31 = posib_254 + 1;
   bit_189 = _30 & _31;
@@ -1030,15 +1037,16 @@ uint64_t nqueens (uint_fast8_t n)
   new_diagl_191 = _32 | diagl_shifted_255;
   _33 = bit_189 >> 1;
   new_diagr_192 = _33 | diagr_shifted_256;
-  bit_193 = bit_189 | prephitmp_380;
+  _34 = cols[d_252];
+  bit_193 = _34 | bit_189;