Diagnose just-past-the-end references for minor array bounds.

Resolves:
PR tree-optimization/84079 - missing -Warray-bounds taking the address of past-the-end element of a multidimensional array

gcc/ChangeLog:

	PR tree-optimization/84079
	* gimple-array-bounds.cc (array_bounds_checker::check_addr_expr):
	Only allow just-past-the-end references for the most significant
	array bound.

gcc/testsuite/ChangeLog:

	PR tree-optimization/84079
	* gcc.dg/Warray-bounds-62.c: New test.

1 files changed, 9 insertions, 2 deletions

diff --git a/gcc/gimple-array-bounds.cc b/gcc/gimple-array-bounds.cc
index 352d074..c2dd666 100644
--- a/gcc/gimple-array-bounds.cc
+++ b/gcc/gimple-array-bounds.cc
@@ -519,14 +519,21 @@ array_bounds_checker::check_mem_ref (location_t location, tree ref,
 void
 array_bounds_checker::check_addr_expr (location_t location, tree t)
 {
+  /* For the most significant subscript only, accept taking the address
+     of the just-past-the-end element.  */
+  bool ignore_off_by_one = true;
+
   /* Check each ARRAY_REF and MEM_REF in the reference chain. */
   do
     {
       bool warned = false;
       if (TREE_CODE (t) == ARRAY_REF)
-	warned = check_array_ref (location, t, true /*ignore_off_by_one*/);
+	{
+	  warned = check_array_ref (location, t, ignore_off_by_one);
+	  ignore_off_by_one = false;
+	}
       else if (TREE_CODE (t) == MEM_REF)
-	warned = check_mem_ref (location, t, true /*ignore_off_by_one*/);
+	warned = check_mem_ref (location, t, ignore_off_by_one);
 
       if (warned)
 	TREE_NO_WARNING (t) = true;