From 8341e6d9fac83d43241273a6c196387f44d5b2f4 Mon Sep 17 00:00:00 2001
From: rguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Thu, 28 Jan 2010 14:45:09 +0000
Subject: [PATCH] 2010-01-28  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/42871
	* tree-ssa-pre.c (phi_translate_set): Make sure to retain
	leaders.

	* g++.dg/torture/pr42871.C: New testcase.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@156324 138bc75d-0d04-0410-961f-82ee72b054a4
---
 gcc/ChangeLog                          |  6 +++++
 gcc/testsuite/ChangeLog                |  5 +++++
 gcc/testsuite/g++.dg/torture/pr42871.C | 40 ++++++++++++++++++++++++++++++++++
 gcc/tree-ssa-pre.c                     | 14 +++++++++---
 4 files changed, 62 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/torture/pr42871.C

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 23cc5778320..ff0e868649b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,11 @@
 2010-01-28  Richard Guenther  <rguenther@suse.de>
 
+	PR tree-optimization/42871
+	* tree-ssa-pre.c (phi_translate_set): Make sure to retain
+	leaders.
+
+2010-01-28  Richard Guenther  <rguenther@suse.de>
+
 	* tree-ssa-ccp.c (ccp_fold_stmt): Fold calls and propagate
 	into call arguments.
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a1c2ba3aff8..42796962341 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,10 @@
 2010-01-28  Richard Guenther  <rguenther@suse.de>
 
+	PR tree-optimization/42871
+	* g++.dg/torture/pr42871.C: New testcase.
+
+2010-01-28  Richard Guenther  <rguenther@suse.de>
+
 	* gcc.dg/Wobjsize-1.h: New testcase.
 	* gcc.dg/Wobjsize-1.c: Likewise.
 
diff --git a/gcc/testsuite/g++.dg/torture/pr42871.C b/gcc/testsuite/g++.dg/torture/pr42871.C
new file mode 100644
index 00000000000..452ad9319fe
--- /dev/null
+++ b/gcc/testsuite/g++.dg/torture/pr42871.C
@@ -0,0 +1,40 @@
+struct C
+{
+  ~C ();
+  int c3;
+};
+
+C *b2;
+
+static void
+b1 (const C &x, unsigned b3, unsigned b4)
+{
+  unsigned i = 0;
+  for (; i < b3; i++)
+    if (i < b4)
+      {
+        b2[0].c3 = x.c3;
+        return;
+      }
+}
+
+int a ();
+
+void
+bar (unsigned b3, unsigned b4)
+{
+  C c[100];
+  for (int i = 0; i < 100; i++)
+    {
+      c[i].c3 = i;
+      for (int j = 0; j < b3; j++)
+        if (j < b4)
+          {
+            b2[0].c3 = 0;
+            break;
+          }
+      b1 (c[i], b3, b4);
+      a ();
+    }
+}
+
diff --git a/gcc/tree-ssa-pre.c b/gcc/tree-ssa-pre.c
index c1e5cd7c701..285b2c8b0b3 100644
--- a/gcc/tree-ssa-pre.c
+++ b/gcc/tree-ssa-pre.c
@@ -1836,10 +1836,18 @@ phi_translate_set (bitmap_set_t dest, bitmap_set_t set, basic_block pred,
       translated = phi_translate (expr, set, NULL, pred, phiblock);
 
       /* Don't add empty translations to the cache  */
-      if (translated)
-	phi_trans_add (expr, translated, pred);
+      if (!translated)
+	continue;
+
+      phi_trans_add (expr, translated, pred);
 
-      if (translated != NULL)
+      /* We might end up with multiple expressions from SET being
+	 translated to the same value.  In this case we do not want
+	 to retain the NARY or REFERENCE expression but prefer a NAME
+	 which would be the leader.  */
+      if (translated->kind == NAME)
+	bitmap_value_replace_in_set (dest, translated);
+      else
 	bitmap_value_insert_into_set (dest, translated);
     }
   VEC_free (pre_expr, heap, exprs);
-- 
2.11.4.GIT