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* [Bug tree-optimization/101548] New: dependence analysis fails with .MASK_STORE @ 2021-07-21 9:13 rguenth at gcc dot gnu.org 2021-07-21 9:15 ` [Bug tree-optimization/101548] " rguenth at gcc dot gnu.org ` (2 more replies) 0 siblings, 3 replies; 4+ messages in thread From: rguenth at gcc dot gnu.org @ 2021-07-21 9:13 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101548 Bug ID: 101548 Summary: dependence analysis fails with .MASK_STORE Product: gcc Version: 12.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: rguenth at gcc dot gnu.org Target Milestone: --- We fail to vectorize (with -fno-trapping-math in case COND_ADD is not available) double a[1024], b[1024]; void foo () { for (int i = 0; i < 1024; ++i) if (b[i] < 3.) a[i] += b[i]; } the loop is if-converted to <bb 3> [local count: 1063004409]: # i_13 = PHI <i_9(7), 0(15)> # ivtmp_6 = PHI <ivtmp_4(7), 1024(15)> _1 = b[i_13]; _2 = a[i_13]; _3 = _1 + _2; _24 = _1 < 3.0e+0; _25 = &a[i_13]; .MASK_STORE (_25, 64B, _24, _3); i_9 = i_13 + 1; ivtmp_4 = ivtmp_6 - 1; if (ivtmp_4 != 0) goto <bb 7>; [98.99%] else goto <bb 6>; [1.01%] but then dependence analysis fails: (compute_affine_dependence ref_a: b[i_13], stmt_a: _1 = b[i_13]; ref_b: *_25, stmt_b: .MASK_STORE (_25, 64B, _24, _3); ) -> no dependence (compute_affine_dependence ref_a: a[i_13], stmt_a: _2 = a[i_13]; ref_b: *_25, stmt_b: .MASK_STORE (_25, 64B, _24, _3); ) -> dependence analysis failed t3.c:7:12: missed: versioning for alias required: can't determine dependence between a[i_13] and *_25 consider run-time aliasing test between a[i_13] and *_25 and then t3.c:5:21: note: === vect_prune_runtime_alias_test_list === t3.c:5:21: note: can tell at compile time that a[i_13] and *_25 alias t3.c:7:12: missed: not vectorized: compilation time alias: _2 = a[i_13]; .MASK_STORE (_25, 64B, _24, _3); and we give up. But the may-dependence does not prevent vectorization. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/101548] dependence analysis fails with .MASK_STORE 2021-07-21 9:13 [Bug tree-optimization/101548] New: dependence analysis fails with .MASK_STORE rguenth at gcc dot gnu.org @ 2021-07-21 9:15 ` rguenth at gcc dot gnu.org 2021-08-03 13:08 ` rguenth at gcc dot gnu.org 2021-09-08 11:08 ` rguenth at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: rguenth at gcc dot gnu.org @ 2021-07-21 9:15 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101548 --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- It works with void foo (double * __restrict a, double *b) { for (int i = 0; i < 1024; ++i) { double tem = a[i]; if (b[i] < tem) a[i] = tem + b[i]; } } and <bb 3> [local count: 1063004409]: # i_20 = PHI <i_15(7), 0(15)> # ivtmp_19 = PHI <ivtmp_18(7), 1024(15)> _1 = (long unsigned int) i_20; _2 = _1 * 8; _3 = a_11(D) + _2; tem_12 = *_3; _4 = b_13(D) + _2; _5 = *_4; _6 = _5 + tem_12; _34 = _5 < tem_12; .MASK_STORE (_3, 64B, _34, _6); i_15 = i_20 + 1; ivtmp_18 = ivtmp_19 - 1; if (ivtmp_18 != 0) goto <bb 7>; [98.99%] else goto <bb 6>; [1.01%] so this is likely a duplicate of the old issue of refs based on a pointer (which .MASK_STORE with &a[i] is) wrt refs based not on a pointer (a[i]). ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/101548] dependence analysis fails with .MASK_STORE 2021-07-21 9:13 [Bug tree-optimization/101548] New: dependence analysis fails with .MASK_STORE rguenth at gcc dot gnu.org 2021-07-21 9:15 ` [Bug tree-optimization/101548] " rguenth at gcc dot gnu.org @ 2021-08-03 13:08 ` rguenth at gcc dot gnu.org 2021-09-08 11:08 ` rguenth at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: rguenth at gcc dot gnu.org @ 2021-08-03 13:08 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101548 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |crazylht at gmail dot com --- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> --- *** Bug 101752 has been marked as a duplicate of this bug. *** ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/101548] dependence analysis fails with .MASK_STORE 2021-07-21 9:13 [Bug tree-optimization/101548] New: dependence analysis fails with .MASK_STORE rguenth at gcc dot gnu.org 2021-07-21 9:15 ` [Bug tree-optimization/101548] " rguenth at gcc dot gnu.org 2021-08-03 13:08 ` rguenth at gcc dot gnu.org @ 2021-09-08 11:08 ` rguenth at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: rguenth at gcc dot gnu.org @ 2021-09-08 11:08 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101548 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution|--- |DUPLICATE --- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> --- quite exact duplicate *** This bug has been marked as a duplicate of bug 65206 *** ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-09-08 11:08 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-07-21 9:13 [Bug tree-optimization/101548] New: dependence analysis fails with .MASK_STORE rguenth at gcc dot gnu.org 2021-07-21 9:15 ` [Bug tree-optimization/101548] " rguenth at gcc dot gnu.org 2021-08-03 13:08 ` rguenth at gcc dot gnu.org 2021-09-08 11:08 ` rguenth at gcc dot gnu.org
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