re PR c++/89698 (Run-time error due to optimization of field access after cast…

re PR c++/89698 (Run-time error due to optimization of field access after cast at -Os/-O2 and higher)

2019-03-14  Richard Biener  <rguenther@suse.de>

	PR middle-end/89698
	* fold-const.c (operand_equal_p): For INDIRECT_REF check
	that the access types are similar.

	* g++.dg/torture/pr89698.C: New testcase.

From-SVN: r269677

gcc/ChangeLog

+2019-03-14  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/89698
+	* fold-const.c (operand_equal_p): For INDIRECT_REF check
+	that the access types are similar.
+
 2019-03-14  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/89703

gcc/fold-const.c

@@ -3220,10 +3220,16 @@ operand_equal_p (const_tree arg0, const_tree arg1, unsigned int flags)
       switch (TREE_CODE (arg0))
 	{
 	case INDIRECT_REF:
-	  if (!(flags & OEP_ADDRESS_OF)
-	      && (TYPE_ALIGN (TREE_TYPE (arg0))
-		  != TYPE_ALIGN (TREE_TYPE (arg1))))
-	    return 0;
+	  if (!(flags & OEP_ADDRESS_OF))
+	    {
+	      if (TYPE_ALIGN (TREE_TYPE (arg0))
+		  != TYPE_ALIGN (TREE_TYPE (arg1)))
+		return 0;
+	      /* Verify that the access types are compatible.  */
+	      if (TYPE_MAIN_VARIANT (TREE_TYPE (arg0))
+		  != TYPE_MAIN_VARIANT (TREE_TYPE (arg1)))
+		return 0;
+	    }
 	  flags &= ~OEP_ADDRESS_OF;
 	  return OP_SAME (0);
 

gcc/testsuite/ChangeLog

+2019-03-14  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/89698
+	* g++.dg/torture/pr89698.C: New testcase.
+
 2019-03-14  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/89703

gcc/testsuite/g++.dg/torture/pr89698.C

+/* { dg-do run } */
+
+extern "C" void abort (void);
+
+class A {
+    virtual void f(){};
+public:
+    int x;
+    A(int in): x(in) {};
+};
+
+class B: public A {
+public:
+    int y;
+    B(int in):A(in-1), y(in) {};
+};
+
+int test(void)
+{
+  int res;
+  B b(2);
+  A* bp = &b;
+  void* vp = dynamic_cast<void*>(bp);
+  if (((A*)vp)->x == 1 && ((B*)vp)->y == 2)
+    return 1;
+  return 0;
+}
+int main() { if (test() != 1) abort (); return 0; }