re PR tree-optimization/56854 (error: non-decl/MEM_REF LHS in clobber statement)

	PR tree-optimization/56854
	* tree-ssa-forwprop.c (forward_propagate_addr_expr_1): Don't
	forward into clobber stmts if it would change MEM_REF lhs into
	non-MEM_REF.

	* g++.dg/torture/pr56854.C: New test.

From-SVN: r197625

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d25241f42691ae4e7bd1ec02ba600dd7018782ee..407676933695d3f2eee37f5ab5515e8a5029913b 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2013-04-09  Jakub Jelinek  <jakub@redhat.com>
+
+       PR tree-optimization/56854
+       * tree-ssa-forwprop.c (forward_propagate_addr_expr_1): Don't
+       forward into clobber stmts if it would change MEM_REF lhs into
+       non-MEM_REF.
+
 2013-04-09  Maxim Kuvyrkov  <maxim@kugelworks.com>
 
        * tree.c (type_hash_lookup, type_hash_add): Make static.

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 73935171e31993b944f6ebe5c6dec34a075f431c..dac8f36bc7a1cb226dcf133677065f88798fe5d6 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2013-04-09  Jakub Jelinek  <jakub@redhat.com>
+
+       PR tree-optimization/56854
+       * g++.dg/torture/pr56854.C: New test.
+
 2013-04-08  Thomas Koenig  <tkoenig@gcc.gnu.org>
 
        PR fortran/56782

diff --git a/gcc/testsuite/g++.dg/torture/pr56854.C b/gcc/testsuite/g++.dg/torture/pr56854.C
new file mode 100644 (file)
index 0000000..fc7e302
--- /dev/null
+++ b/gcc/testsuite/g++.dg/torture/pr56854.C
@@ -0,0 +1,24 @@
+// PR tree-optimization/56854
+// { dg-do compile }
+
+inline void *
+operator new (__SIZE_TYPE__, void *p) throw ()
+{
+  return p;
+}
+
+struct A
+{
+  int a;
+  A () : a (0) {}
+  ~A () {}
+  A &operator= (const A &v) { this->~A (); new (this) A (v); return *this; }
+};
+A b[4], c[4];
+
+void
+foo ()
+{
+  for (int i = 0; i < 4; ++i)
+    c[i] = b[i];
+}

diff --git a/gcc/tree-ssa-forwprop.c b/gcc/tree-ssa-forwprop.c
index edcf92918b7d597e704222cee4d447c3c2e9a6dd..26b076146d3aa0271d6fd640a0653278fe5e2835 100644 (file)
--- a/gcc/tree-ssa-forwprop.c
+++ b/gcc/tree-ssa-forwprop.c
@@ -826,7 +826,11 @@ forward_propagate_addr_expr_1 (tree name, tree def_rhs,
               && integer_zerop (TREE_OPERAND (lhs, 1))
               && useless_type_conversion_p
                    (TREE_TYPE (TREE_OPERAND (def_rhs, 0)),
-                    TREE_TYPE (gimple_assign_rhs1 (use_stmt))))
+                    TREE_TYPE (gimple_assign_rhs1 (use_stmt)))
+              /* Don't forward anything into clobber stmts if it would result
+                 in the lhs no longer being a MEM_REF.  */
+              && (!gimple_clobber_p (use_stmt)
+                  || TREE_CODE (TREE_OPERAND (def_rhs, 0)) == MEM_REF))
        {
          tree *def_rhs_basep = &TREE_OPERAND (def_rhs, 0);
          tree new_offset, new_base, saved, new_lhs;