changeset 54610:6bf8877eb1b9

8220374: C2: LoopStripMining doesn't strip as expected Reviewed-by: rkennke, thartmann, mdoerr
author roland
date Tue, 12 Mar 2019 15:42:32 +0100
parents d611b76d1327
children 677cede5608e
files src/hotspot/share/opto/loopnode.cpp test/hotspot/jtreg/compiler/loopstripmining/CheckLoopStripMining.java
diffstat 2 files changed, 64 insertions(+), 6 deletions(-) [+]
line wrap: on
line diff
--- a/src/hotspot/share/opto/loopnode.cpp	Thu Mar 14 12:30:57 2019 +0100
+++ b/src/hotspot/share/opto/loopnode.cpp	Tue Mar 12 15:42:32 2019 +0100
@@ -1593,12 +1593,17 @@
     } else {
       new_limit = igvn->transform(new SubINode(iv_phi, min));
     }
-    Node* cmp = inner_cle->cmp_node()->clone();
-    igvn->replace_input_of(cmp, 2, new_limit);
-    Node* bol = inner_cle->in(CountedLoopEndNode::TestValue)->clone();
-    cmp->set_req(2, limit);
-    bol->set_req(1, igvn->transform(cmp));
-    igvn->replace_input_of(outer_loop_end(), 1, igvn->transform(bol));
+    Node* inner_cmp = inner_cle->cmp_node();
+    Node* inner_bol = inner_cle->in(CountedLoopEndNode::TestValue);
+    Node* outer_bol = inner_bol;
+    // cmp node for inner loop may be shared
+    inner_cmp = inner_cmp->clone();
+    inner_cmp->set_req(2, new_limit);
+    inner_bol = inner_bol->clone();
+    inner_bol->set_req(1, igvn->transform(inner_cmp));
+    igvn->replace_input_of(inner_cle, CountedLoopEndNode::TestValue, igvn->transform(inner_bol));
+    // Set the outer loop's exit condition too
+    igvn->replace_input_of(outer_loop_end(), 1, outer_bol);
   } else {
     assert(false, "should be able to adjust outer loop");
     IfNode* outer_le = outer_loop_end();
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/jtreg/compiler/loopstripmining/CheckLoopStripMining.java	Tue Mar 12 15:42:32 2019 +0100
@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2019, SAP SE. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @bug 8220374
+ * @summary C2: LoopStripMining doesn't strip as expected
+ * @requires vm.compiler2.enabled
+ *
+ * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+SafepointTimeout -XX:+SafepointALot
+ *                   -XX:+AbortVMOnSafepointTimeout -XX:SafepointTimeoutDelay=500 -XX:GuaranteedSafepointInterval=500
+ *                   -XX:-TieredCompilation -XX:+UseCountedLoopSafepoints -XX:LoopStripMiningIter=1000
+ *                   -XX:LoopUnrollLimit=0 -XX:CompileCommand=compileonly,CheckLoopStripMining::test_loop -Xcomp CheckLoopStripMining
+ *
+ */
+
+public class CheckLoopStripMining {
+
+  public static int test_loop(int x) {
+      int sum = 0;
+      if (x != 0) {
+          for (int y = 1; y < Integer.MAX_VALUE; ++y) {
+              if (y % x == 0) ++sum;
+          }
+      }
+      return sum;
+  }
+
+  public static void main(String args[]) {
+    int sum = test_loop(3);
+    System.out.println("sum: " + sum);
+  }
+}