re PR tree-optimization/61140 (wrong code at -O1 and above on x86_64-linux-gnu)

2014-05-17  Marc Glisse  <marc.glisse@inria.fr>

	PR tree-optimization/61140
	PR tree-optimization/61150
	PR tree-optimization/61197
gcc/
	* tree-ssa-phiopt.c (value_replacement): Punt on multiple phis.
gcc/testsuite/
	* gcc.dg/tree-ssa/pr61140.c: New file.
	* gcc.dg/tree-ssa/pr61150.c: New file.
	* gcc.dg/tree-ssa/pr61197.c: New file.

From-SVN: r210554

gcc/ChangeLog

+2014-05-17  Marc Glisse  <marc.glisse@inria.fr>
+
+	PR tree-optimization/61140
+	PR tree-optimization/61150
+	PR tree-optimization/61197
+	* tree-ssa-phiopt.c (value_replacement): Punt on multiple phis.
+
 2014-05-17  Uros Bizjak  <ubizjak@gmail.com>
 
 	* doc/invoke.texi (free): Mention Alpha.  Also enabled at -Os.

gcc/testsuite/ChangeLog

+2014-05-17  Marc Glisse  <marc.glisse@inria.fr>
+
+	PR tree-optimization/61140
+	PR tree-optimization/61150
+	PR tree-optimization/61197
+	* gcc.dg/tree-ssa/pr61140.c: New file.
+	* gcc.dg/tree-ssa/pr61150.c: New file.
+	* gcc.dg/tree-ssa/pr61197.c: New file.
+
 2014-05-17  Uros Bizjak  <ubizjak@gmail.com>
 
 	* g++.dg/pr60969.C: Compile for all ilp32 x86 targets.

gcc/testsuite/gcc.dg/tree-ssa/pr61140.c

+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+int a[1] = { 1 }, b = 1, c; 
+
+int
+main ()
+{
+  for (; c < 1; c++)
+    if (a[0])
+    {
+      a[0] &= 1;
+      b = 0;
+    }
+  if (b)
+    __builtin_abort ();
+  return 0;
+}

gcc/testsuite/gcc.dg/tree-ssa/pr61150.c

+/* { dg-do run } */
+/* { dg-options "-O3" } */
+
+int a, b, c, d = 1;
+
+int
+main ()
+{
+  int e = d;
+  for (b = 0; b < 5; b++)
+  {
+    for (a = 0; a < 1; a++)
+    {
+      if (e)
+	break;
+      for (c = 0; c < 1; c++)
+	;
+    }
+    e |= 1;
+  }
+  if (c)
+    __builtin_abort();
+  return 0;
+}

gcc/testsuite/gcc.dg/tree-ssa/pr61197.c

+/* { dg-do run } */
+/* { dg-options "-O3" } */
+
+int a, b = 1, *c = &a; 
+
+int
+foo ()
+{
+  if (b)
+    b |= 1;
+  else
+    {
+      b = 1;
+      return 0;
+    }
+  return 1;
+}
+
+int
+main ()
+{
+  *c = foo ();
+  if (a != 1) 
+    __builtin_abort (); 
+  return 0;
+}

gcc/tree-ssa-phiopt.c

@@ -849,6 +849,10 @@ value_replacement (basic_block cond_bb, basic_block middle_bb,
 	  && !POINTER_TYPE_P (TREE_TYPE (arg0))))
     return 0;
 
+  /* Only transform if it removes the condition.  */
+  if (!single_non_singleton_phi_for_edges (phi_nodes (gimple_bb (phi)), e0, e1))
+    return 0;
+
   /* Size-wise, this is always profitable.  */
   if (optimize_bb_for_speed_p (cond_bb)
       /* The special case is useless if it has a low probability.  */