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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/96481] SLP fail to vectorize VEC_COND_EXPR pattern. Date: Wed, 05 Aug 2020 11:26:23 +0000 [thread overview] Message-ID: <bug-96481-4-WPtL8zzkBT@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-96481-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96481 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |missed-optimization Last reconfirmed| |2020-08-05 Ever confirmed|0 |1 Status|UNCONFIRMED |NEW Blocks| |53947 --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- Yes, this is a known limitation in that for basic-block SLP we do not perform if-conversion. Instead the basic-block SLP code sees <bb 2> [local count: 1073741824]: _1 = *pd_17(D); _2 = *pc_19(D); _3 = *pb_20(D); _4 = *pa_21(D); if (_3 < _4) goto <bb 11>; [50.00%] else goto <bb 3>; [50.00%] <bb 11> [local count: 536870912]: goto <bb 4>; [100.00%] <bb 3> [local count: 536870913]: <bb 4> [local count: 1073741824]: # iftmp.20_23 = PHI <_1(3), _2(11)> *dst_22(D) = iftmp.20_23; _5 = MEM[(const unsigned int *)pd_17(D) + 4B]; _6 = MEM[(const unsigned int *)pc_19(D) + 4B]; _7 = MEM[(const unsigned int *)pb_20(D) + 4B]; _8 = MEM[(const unsigned int *)pa_21(D) + 4B]; ... which also rips apart the memory groups (we're slowly relaxing another limitation that the basic-block SLP code operates on a single basic-block at a time but for data refs this restriction will prevail). Referenced Bugs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53947 [Bug 53947] [meta-bug] vectorizer missed-optimizations
next prev parent reply other threads:[~2020-08-05 11:26 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-08-05 9:26 [Bug tree-optimization/96481] New: " crazylht at gmail dot com 2020-08-05 11:26 ` rguenth at gcc dot gnu.org [this message] 2020-08-05 11:28 ` [Bug tree-optimization/96481] " rguenth at gcc dot gnu.org 2020-08-05 11:30 ` rguenth at gcc dot gnu.org 2020-08-10 3:20 ` marxin at gcc dot gnu.org 2021-08-19 23:13 ` pinskia at gcc dot gnu.org 2021-08-20 9:18 ` rguenth at gcc dot gnu.org 2021-08-20 10:46 ` rguenth at gcc dot gnu.org
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