PR tree-optimization/89662 - -Warray-bounds ICE on void* arithmetic

gcc/ChangeLog:

	PR tree-optimization/89662
	* tree-vrp.c (vrp_prop::check_mem_ref): Avoid assuming every type
	has a size.

gcc/testsuite/ChangeLog:

	PR tree-optimization/89662
	* gcc.dg/Warray-bounds-41.c: New test.

From-SVN: r269655

gcc/ChangeLog

+2019-03-13  Martin Sebor  <msebor@redhat.com>
+
+	PR tree-optimization/89662
+	* tree-vrp.c (vrp_prop::check_mem_ref): Avoid assuming every type
+	has a size.
+
 2019-03-13  Richard Biener  <rguenther@suse.de>
 
 	PR middle-end/89677

gcc/testsuite/ChangeLog

+2019-03-13  Martin Sebor  <msebor@redhat.com>
+
+	PR tree-optimization/89662
+	* gcc.dg/Warray-bounds-41.c: New test.
+
 2019-03-13  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/63508

gcc/testsuite/gcc.dg/Warray-bounds-41.c

+/* PR tree-optimization/89662- -Warray-bounds ICE on void* arithmetic
+   { dg-do compile }
+   { dg-options "-O2 -Wall" } */
+
+void* vptr (void *c)
+{
+  return c;
+}
+
+void sink (void*);
+
+void test_vptr_arith_vla_cst (void)
+{
+  int n = 1;
+  char c[n];
+  sink (vptr (c) - 1);    /* { dg-warning "\\\[-Warray-bounds" } */
+}
+
+void test_vptr_arith_vla_range (int n)
+{
+  if (n < 1 || 4 < n)
+    return;
+
+  char c[n];
+  sink (vptr (c) - 1);    /* { dg-warning "\\\[-Warray-bounds" "pr82608" { xfail *-*-* } } */
+}
+
+void test_vptr_arith_vla_var (int n)
+{
+  char c[n];
+  sink (vptr (c) - 1);    /* { dg-warning "\\\[-Warray-bounds" "pr82608" { xfail *-*-* } } */
+}
+

gcc/tree-vrp.c

@@ -4718,13 +4718,16 @@ vrp_prop::check_mem_ref (location_t location, tree ref,
 	{
 	  /* Extract the element type out of MEM_REF and use its size
 	     to compute the index to print in the diagnostic; arrays
-	     in MEM_REF don't mean anything.   */
+	     in MEM_REF don't mean anything.  A type with no size like
+	     void is as good as having a size of 1.  */
 	  tree type = TREE_TYPE (ref);
 	  while (TREE_CODE (type) == ARRAY_TYPE)
 	    type = TREE_TYPE (type);
-	  tree size = TYPE_SIZE_UNIT (type);
-	  offrange[0] = offrange[0] / wi::to_offset (size);
-	  offrange[1] = offrange[1] / wi::to_offset (size);
+	  if (tree size = TYPE_SIZE_UNIT (type))
+	    {
+	      offrange[0] = offrange[0] / wi::to_offset (size);
+	      offrange[1] = offrange[1] / wi::to_offset (size);
+	    }
 	}
       else
 	{