From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1666) id D3E98384B12B; Thu, 6 Oct 2022 10:07:33 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org D3E98384B12B DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1665050853; bh=sN/ttxfEUNWg/AyHszLV0UBkp7UFpvMQqCQgImz55Ic=; h=From:To:Subject:Date:From; b=iDjFLg2PmOcEdqXvrmu7IB8yKiKgLPOedKE6PsNLHPDoxmo6fhIqYLME0aiBN9p5N tXDeYYhYgj8vBWu+UBoagFVX54elAfHYdSrg/sH3AtGmn/wPBKC7evkre8ziulxeG5 Vm+RNcqmuiAteFko3B48eHenAfBA/Cb8t5x2cdS4= MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Richard Biener To: gcc-cvs@gcc.gnu.org Subject: [gcc r13-3126] tree-optimization/107107 - tail-merging VN wrong-code X-Act-Checkin: gcc X-Git-Author: Richard Biener X-Git-Refname: refs/heads/master X-Git-Oldrev: 544d14e1b42eeb337fcefb1efe9d108e71a06d52 X-Git-Newrev: 85333b9265720fc4e49397301cb16324d2b89aa7 Message-Id: <20221006100733.D3E98384B12B@sourceware.org> Date: Thu, 6 Oct 2022 10:07:33 +0000 (GMT) List-Id: https://gcc.gnu.org/g:85333b9265720fc4e49397301cb16324d2b89aa7 commit r13-3126-g85333b9265720fc4e49397301cb16324d2b89aa7 Author: Richard Biener Date: Thu Oct 6 11:20:16 2022 +0200 tree-optimization/107107 - tail-merging VN wrong-code The following fixes an unintended(?) side-effect of the special MODIFY_EXPR expression entries we add for tail-merging during VN. We shouldn't value-number the virtual operand differently here. PR tree-optimization/107107 * tree-ssa-sccvn.cc (visit_reference_op_store): Do not affect value-numbering when doing the tail merging MODIFY_EXPR lookup. * gcc.dg/pr107107.c: New testcase. Diff: --- gcc/testsuite/gcc.dg/pr107107.c | 25 +++++++++++++++++++++++++ gcc/tree-ssa-sccvn.cc | 17 +++-------------- 2 files changed, 28 insertions(+), 14 deletions(-) diff --git a/gcc/testsuite/gcc.dg/pr107107.c b/gcc/testsuite/gcc.dg/pr107107.c new file mode 100644 index 00000000000..5ad6a63159e --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr107107.c @@ -0,0 +1,25 @@ +/* { dg-do run } */ +/* { dg-options "-O2 -ftree-tail-merge" } */ + +static inline void set_longish(int is_long_long, void *p, long x) +{ + if (is_long_long) + *(long long*)p = x; + else + *(long*)p = x; +} +static long test(long long *p, int index, int mode) +{ + *p = 1; + set_longish(mode, p+index, 2); + return *p; +} +long (*volatile vtest)(long long*, int, int) = test; +int main(void) +{ + long long x; + long result = vtest(&x, 0, 1); + if (result != 2 || x != 2) + __builtin_abort (); + return 0; +} diff --git a/gcc/tree-ssa-sccvn.cc b/gcc/tree-ssa-sccvn.cc index 2cc2c0e1e34..37484403c56 100644 --- a/gcc/tree-ssa-sccvn.cc +++ b/gcc/tree-ssa-sccvn.cc @@ -5718,19 +5718,6 @@ visit_reference_op_store (tree lhs, tree op, gimple *stmt) if (!resultsame) { - /* Only perform the following when being called from PRE - which embeds tail merging. */ - if (default_vn_walk_kind == VN_WALK) - { - assign = build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, op); - vn_reference_lookup (assign, vuse, VN_NOWALK, &vnresult, false); - if (vnresult) - { - VN_INFO (vdef)->visited = true; - return set_ssa_val_to (vdef, vnresult->result_vdef); - } - } - if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "No store match\n"); @@ -5755,7 +5742,9 @@ visit_reference_op_store (tree lhs, tree op, gimple *stmt) if (default_vn_walk_kind == VN_WALK) { assign = build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, op); - vn_reference_insert (assign, lhs, vuse, vdef); + vn_reference_lookup (assign, vuse, VN_NOWALK, &vnresult, false); + if (!vnresult) + vn_reference_insert (assign, lhs, vuse, vdef); } } else