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From: "crazylht at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c/105363] -ftree-slp-vectorize decreases performance significantly (x64) Date: Mon, 25 Apr 2022 03:16:28 +0000 [thread overview] Message-ID: <bug-105363-4-KYoH4XVw9o@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-105363-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105363 Hongtao.liu <crazylht at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |crazylht at gmail dot com --- Comment #1 from Hongtao.liu <crazylht at gmail dot com> --- STLF issues here. Performance counter stats for './12.out': 1,248,728,604 ld_blocks.store_forward:u 5.756169101 seconds time elapsed 5.746946000 seconds user 0.001999000 seconds sys and this case doens't need IPA, it's SLP inside the loop which has cross-iteration data-dependence, I think we need to prevent that. #define N 50000 int a[N]; void insertionsort(int a[], int n) { int i, j; for (i = 1; i < n; i++) { for (j = i-1; j >= 0 && a[j] > a[j+1]; j--) { int t = a[j+1]; a[j+1] = a[j]; a[j] = t; } } } dump: <bb 5> [local count: 958878294]: MEM <vector(2) int> [(int *)_37] = vect__4.9_45; ivtmp.17_47 = ivtmp.17_28 + 18446744073709551612; if (_11 != ivtmp.17_47) goto <bb 7>; [94.50%] else goto <bb 6>; [5.50%] <bb 6> [local count: 114863531]: ivtmp.25_50 = ivtmp.25_9 + 1; ivtmp.28_52 = ivtmp.28_51 + 4; if (ivtmp.25_50 != _59) goto <bb 4>; [89.00%] else goto <bb 8>; [11.00%] <bb 7> [local count: 1014686024]: # ivtmp.17_28 = PHI <ivtmp.17_47(5), _61(4)> _37 = (void *) ivtmp.17_28; vect__8.8_46 = MEM <vector(2) int> [(int *)_37]; vect__4.9_45 = VEC_PERM_EXPR <vect__8.8_46, vect__8.8_46, { 1, 0 }>; _43 = BIT_FIELD_REF <vect__8.8_46, 32, 0>; _44 = BIT_FIELD_REF <vect__8.8_46, 32, 32>; if (_43 > _44) goto <bb 5>; [94.50%] else goto <bb 6>; [5.50%] <bb 8> [local count: 14196616]:
next prev parent reply other threads:[~2022-04-25 3:16 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-04-24 14:25 [Bug c/105363] New: " mtzguido at gmail dot com 2022-04-25 3:16 ` crazylht at gmail dot com [this message] 2022-04-25 3:37 ` [Bug c/105363] " crazylht at gmail dot com 2022-04-25 7:21 ` [Bug tree-optimization/105363] " rguenth at gcc dot gnu.org
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