Rebuild array with the updated function pointer type

When we apply function attribute to array of function pointer, we need
to rebuild array with the updated function pointer type.

gcc/

	PR c/68637
	* attribs.c (decl_attributes): Rebuild array with the updated
	function pointer type.

gcc/testsuite/

	PR c/68637
	* gcc.target/i386/pr68637-1.c: New test.
	* gcc.target/i386/pr68637-2.c: Likewise.

3 files changed, 52 insertions, 1 deletions

diff --git a/gcc/attribs.c b/gcc/attribs.c
index 9a886214ec4..c5cc3c5faba 100644
--- a/gcc/attribs.c
+++ b/gcc/attribs.c
@@ -494,9 +494,18 @@ decl_attributes (tree *node, tree attributes, int flags)
 	  flags &= ~(int) ATTR_FLAG_TYPE_IN_PLACE;
 	}
 
+      tree array_type = (TREE_CODE (*anode) == ARRAY_TYPE
+			 ? *anode
+			 : NULL_TREE);
+
       if (spec->function_type_required && TREE_CODE (*anode) != FUNCTION_TYPE
 	  && TREE_CODE (*anode) != METHOD_TYPE)
 	{
+	  /* We need to rebuid array with the updated function pointer
+	     type later. */
+	  if (array_type)
+	    *anode = TREE_TYPE (*anode);
+
 	  if (TREE_CODE (*anode) == POINTER_TYPE
 	      && (TREE_CODE (TREE_TYPE (*anode)) == FUNCTION_TYPE
 		  || TREE_CODE (TREE_TYPE (*anode)) == METHOD_TYPE))
@@ -617,7 +626,14 @@ decl_attributes (tree *node, tree attributes, int flags)
 	  if (fn_ptr_quals)
 	    fn_ptr_tmp = build_qualified_type (fn_ptr_tmp, fn_ptr_quals);
 	  if (DECL_P (*node))
-	    TREE_TYPE (*node) = fn_ptr_tmp;
+	    {
+	      if (array_type)
+		TREE_TYPE (*node)
+		  = build_array_type (fn_ptr_tmp,
+				      TYPE_DOMAIN (array_type));
+	      else
+		TREE_TYPE (*node) = fn_ptr_tmp;
+	    }
 	  else
 	    {
 	      gcc_assert (TREE_CODE (*node) == POINTER_TYPE);
diff --git a/gcc/testsuite/gcc.target/i386/pr68637-1.c b/gcc/testsuite/gcc.target/i386/pr68637-1.c
new file mode 100644
index 00000000000..b1661fd49b2
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68637-1.c
@@ -0,0 +1,10 @@
+/* { dg-do run { target ia32 } } */
+/* { dg-additional-sources pr68637-2.c } */
+
+extern void (*bar[]) (int, int) __attribute__ ((regparm (2)));
+
+void
+foo (void)
+{
+  bar[0] (1, 2);
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr68637-2.c b/gcc/testsuite/gcc.target/i386/pr68637-2.c
new file mode 100644
index 00000000000..7d9654d3070
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr68637-2.c
@@ -0,0 +1,25 @@
+/* { dg-do compile { target ia32 } } */
+
+static void 
+__attribute__ ((regparm (2)))
+bar0 (int i, int j)
+{
+  if (i != 1 || j != 2)
+    __builtin_abort ();
+}
+
+typedef void (*func_t) (int, int) __attribute__ ((regparm (2)));
+
+func_t bar[] =
+{
+  bar0,
+};
+
+extern void foo (void);
+
+int
+main ()
+{
+  foo ();
+  return 0;
+}