re PR tree-optimization/56273 (Bogus -Warray-bounds warning)

2015-01-27  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/56273
	PR tree-optimization/59124
	PR tree-optimization/64277
	* tree-vrp.c (vrp_finalize): Emit array-bound warnings only
	from the first VRP pass.

	* g++.dg/warn/Warray-bounds-6.C: New testcase.
	* gcc.dg/Warray-bounds-12.c: Likewise.
	* gcc.dg/Warray-bounds-13.c: Likewise.

From-SVN: r220157

gcc/ChangeLog

+2015-01-27  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/56273
+	PR tree-optimization/59124
+	PR tree-optimization/64277
+	* tree-vrp.c (vrp_finalize): Emit array-bound warnings only
+	from the first VRP pass.
+
 2015-01-27  Jakub Jelinek  <jakub@redhat.com>
 
 	PR ipa/64776

gcc/testsuite/ChangeLog

+2015-01-27  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/56273
+	PR tree-optimization/59124
+	PR tree-optimization/64277
+	* g++.dg/warn/Warray-bounds-6.C: New testcase.
+	* gcc.dg/Warray-bounds-12.c: Likewise.
+	* gcc.dg/Warray-bounds-13.c: Likewise.
+
 2015-01-27  Jakub Jelinek  <jakub@redhat.com>
 
 	PR rtl-optimization/61058

gcc/testsuite/g++.dg/warn/Warray-bounds-6.C

+// { dg-do compile }
+// { dg-options "-O3 -Warray-bounds" }
+
+struct type {
+    bool a, b;
+    bool get_b() { return b; }
+};
+
+type stuff[9u];
+
+void bar();
+
+void foo()
+{
+  for(unsigned i = 0u; i < 9u; i++)
+    {
+      if(!stuff[i].a)
+	continue;
+
+      bar();
+
+      for(unsigned j = i + 1u; j < 9u; j++)
+	if(stuff[j].a && stuff[j].get_b()) // { dg-bogus "above array bounds" }
+	  return;
+    }
+}

gcc/testsuite/gcc.dg/Warray-bounds-12.c

+/* { dg-do compile } */
+/* { dg-options "-O3 -Warray-bounds" } */
+/* { dg-additional-options "-mssse3" { target x86_64-*-* i?86-*-* } } */
+
+void foo(short a[], short m)
+{
+  int i, j;
+  int f1[10];
+  short nc;
+
+  nc = m + 1;
+  if (nc > 3)
+    {
+      for (i = 0; i <= nc; i++)
+	{
+	  f1[i] = f1[i] + 1;
+	}
+    }
+
+  for (i = 0, j = m; i < nc; i++, j--)
+    {
+      a[i] = f1[i]; /* { dg-bogus "above array bounds" } */
+      a[j] = i;
+    }
+  return;
+}

gcc/testsuite/gcc.dg/Warray-bounds-13.c

+/* { dg-do compile } */
+/* { dg-options "-O3 -Warray-bounds" } */
+
+extern char *bar[17];
+
+int foo(int argc, char **argv)
+{
+  int i;
+  int n = 0;
+
+  for (i = 0; i < argc; i++)
+    n++;
+
+  for (i = 0; i < argc; i++)
+    argv[i] = bar[i + n]; /* { dg-bogus "above array bounds" } */
+
+  return 0;
+}

gcc/tree-vrp.c

@@ -10229,7 +10229,7 @@ vrp_finalize (void)
   substitute_and_fold (op_with_constant_singleton_value_range,
 		       vrp_fold_stmt, false);
 
-  if (warn_array_bounds)
+  if (warn_array_bounds && first_pass_instance)
     check_all_array_refs ();
 
   /* We must identify jump threading opportunities before we release