From a294e6368f80ac27c5150414027d1cf2a21bd9b7 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Tue, 8 Dec 2020 09:45:57 +0100 Subject: [PATCH] tree-optimization/97559 - fix sinking in irreducible regions This fixes sinking of loads when irreducible regions are involved and the heuristics to find stores on the path along the sink breaks down since that uses dominator queries. 2020-12-08 Richard Biener PR tree-optimization/97559 * tree-ssa-sink.c (statement_sink_location): Never ignore PHIs on sink paths in irreducible regions. * gcc.dg/torture/pr97559-1.c: New testcase. * gcc.dg/torture/pr97559-2.c: Likewise. --- gcc/testsuite/gcc.dg/torture/pr97559-1.c | 21 +++++++++++++++++++++ gcc/testsuite/gcc.dg/torture/pr97559-2.c | 18 ++++++++++++++++++ gcc/tree-ssa-sink.c | 14 +++++++++----- 3 files changed, 48 insertions(+), 5 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/torture/pr97559-1.c create mode 100644 gcc/testsuite/gcc.dg/torture/pr97559-2.c diff --git a/gcc/testsuite/gcc.dg/torture/pr97559-1.c b/gcc/testsuite/gcc.dg/torture/pr97559-1.c new file mode 100644 index 00000000000..d5de3bdb39e --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr97559-1.c @@ -0,0 +1,21 @@ +/* { dg-do compile } */ + +int printf (char *, ...); + +int a, b, c, d; + +void e () { + int f = a; + if (b) { + L1: + b = 0; + L2: + if (c) { + if (f) + printf("0"); + goto L1; + } + } + if (d) + goto L2; +} diff --git a/gcc/testsuite/gcc.dg/torture/pr97559-2.c b/gcc/testsuite/gcc.dg/torture/pr97559-2.c new file mode 100644 index 00000000000..b512e6db7ca --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr97559-2.c @@ -0,0 +1,18 @@ +/* { dg-do compile } */ + +int a, b, c, d; + +void e() { + int f = b; + if (a) { + L1: + a = 0; + L2: + if (a) { + c = b; + goto L1; + } + } + if (d) + goto L2; +} diff --git a/gcc/tree-ssa-sink.c b/gcc/tree-ssa-sink.c index 207aae2818a..b0abf4147d6 100644 --- a/gcc/tree-ssa-sink.c +++ b/gcc/tree-ssa-sink.c @@ -390,12 +390,15 @@ statement_sink_location (gimple *stmt, basic_block frombb, with the use. */ if (gimple_code (use_stmt) == GIMPLE_PHI) { - /* In case the PHI node post-dominates the current insert location - we can disregard it. But make sure it is not dominating - it as well as can happen in a CFG cycle. */ + /* In case the PHI node post-dominates the current insert + location we can disregard it. But make sure it is not + dominating it as well as can happen in a CFG cycle. */ if (commondom != bb && !dominated_by_p (CDI_DOMINATORS, commondom, bb) - && dominated_by_p (CDI_POST_DOMINATORS, commondom, bb)) + && dominated_by_p (CDI_POST_DOMINATORS, commondom, bb) + /* If the blocks are possibly within the same irreducible + cycle the above check breaks down. */ + && !(bb->flags & commondom->flags & BB_IRREDUCIBLE_LOOP)) continue; bb = EDGE_PRED (bb, PHI_ARG_INDEX_FROM_USE (use_p))->src; } @@ -407,7 +410,8 @@ statement_sink_location (gimple *stmt, basic_block frombb, continue; /* There is no easy way to disregard defs not on the path from frombb to commondom so just consider them all. */ - commondom = nearest_common_dominator (CDI_DOMINATORS, bb, commondom); + commondom = nearest_common_dominator (CDI_DOMINATORS, + bb, commondom); if (commondom == frombb) return false; } -- 2.30.2