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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/64404] [5 Regression] ICE: in vect_get_vec_def_for_operand, at tree-vect-stmts.c:1464 with --param=sccvn-max-alias-queries-per-access=1 Date: Tue, 13 Jan 2015 09:37:00 -0000 [thread overview] Message-ID: <bug-64404-4-UPIDlBcUEF@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-64404-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64404 --- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> --- Ok, this also shows the (known :/) wrong-code issue we have with the same-dr and mixed SLP / loop vectorization. The vectorizer is fed <bb 3>: # d_16 = PHI <d_13(4), 0(2)> # ivtmp_15 = PHI <ivtmp_14(4), 1024(2)> _4 = X[d_16].l; _5 = X[d_16].h; _6 = _4 + _5; Y[d_16].l = _6; Y[d_16].h = _6; Z[d_16].l = _4; _11 = X[d_16].h; Z[d_16].h = _11; d_13 = d_16 + 1; ivtmp_14 = ivtmp_15 - 1; if (ivtmp_14 != 0) goto <bb 4>; else goto <bb 5>; <bb 4>: goto <bb 3>; where the Y = X op is SLPed but the Z = X one fails to SLP because of the CSEd load (thus SLP analysis figures that the store has gaps). When trying to loop vectorize the Z = X op (by unrolling the loop once) we get at the DEF for _11 which unfortunately is already vectorized with SLP and the vectorized stmt is the one with the load permutation applied. We really are not prepared to vectorize this loop! In fact the second X.h load shouldn't be considered a grouped load, but nothing "splits" it apart again.
next prev parent reply other threads:[~2015-01-13 9:37 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-12-25 8:35 [Bug tree-optimization/64404] New: " zsojka at seznam dot cz 2014-12-25 12:20 ` [Bug tree-optimization/64404] " dominiq at lps dot ens.fr 2015-01-08 9:07 ` rguenth at gcc dot gnu.org 2015-01-13 9:37 ` rguenth at gcc dot gnu.org [this message] 2015-01-13 10:57 ` rguenth at gcc dot gnu.org 2015-01-13 12:36 ` rguenth at gcc dot gnu.org 2015-01-13 12:36 ` rguenth at gcc dot gnu.org
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