tree-ssa-alias.c (indirect_refs_may_alias_p): Do not treat arrays with same type...

2016-12-01  Richard Biener  <rguenther@suse.de>

	* tree-ssa-alias.c (indirect_refs_may_alias_p): Do not
	treat arrays with same type as objects that cannot overlap.

	* gcc.dg/torture/alias-2.c: New testcase.

From-SVN: r243106

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2683757..19cb0ce 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2016-12-01  Richard Biener  <rguenther@suse.de>
+
+       * tree-ssa-alias.c (indirect_refs_may_alias_p): Do not
+       treat arrays with same type as objects that cannot overlap.
+
 2016-12-01  Georg-Johann Lay  <avr@gjlay.de>
 
        * config/avr/avr.c (avr_print_operand): Use SYMBOL_REF_P if possible.

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index ab55b43..447d9fb 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2016-12-01  Richard Biener  <rguenther@suse.de>
+
+       * gcc.dg/torture/alias-2.c: New testcase.
+
 2016-12-01  Georg-Johann Lay  <avr@gjlay.de>
 
        * gcc.target/avr/tiny-memx.c: Only perform if target avr_tiny.

diff --git a/gcc/testsuite/gcc.dg/torture/alias-2.c b/gcc/testsuite/gcc.dg/torture/alias-2.c
new file mode 100644 (file)
index 0000000..329d46a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/alias-2.c
@@ -0,0 +1,17 @@
+/* { dg-do run } */
+
+/* We do not want to treat int[3] as an object that cannot overlap
+   itself but treat it as arbitrary sub-array of a larger array object.  */
+int ar1(int (*p)[3], int (*q)[3])
+{
+  (*p)[0] = 1;
+  (*q)[1] = 2;
+  return (*p)[0];
+}
+int main()
+{
+  int a[4];
+  if (ar1 ((int (*)[3])&a[1], (int (*)[3])&a[0]) != 2)
+    __builtin_abort ();
+  return 0;
+}