From: Alejandro Colomar <alx@kernel.org>
Date: Mon, 10 Nov 2025 19:26:21 +0000 (+0000)
Subject: c: Fix return type of _Countof [PR122591]
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a7f188ccaf721ab04f569a6c140dd1b1c73ab500;p=thirdparty%2Fgcc.git

c: Fix return type of _Countof [PR122591]

	PR c/122591

gcc/c-family/ChangeLog:

	* c-common.cc (c_countof_type): Convert return value to size_t.

gcc/testsuite/ChangeLog:

	* gcc.dg/countof-compile.c (type): Test return type of _Countof.

Reported-by: Sam James <sam@gentoo.org>
Suggested-by: Andrew Pinski <andrew.pinski@oss.qualcomm.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
---

diff --git a/gcc/c-family/c-common.cc b/gcc/c-family/c-common.cc
index 1c382540b38..9b97a0fe622 100644
--- a/gcc/c-family/c-common.cc
+++ b/gcc/c-family/c-common.cc
@@ -4114,6 +4114,7 @@ tree
 c_countof_type (location_t loc, tree type)
 {
   enum tree_code type_code;
+  tree value;
 
   type_code = TREE_CODE (type);
   if (type_code != ARRAY_TYPE)
@@ -4129,7 +4130,12 @@ c_countof_type (location_t loc, tree type)
       return error_mark_node;
     }
 
-  return array_type_nelts_top (type);
+  value = array_type_nelts_top (type);
+  /* VALUE will have the middle-end integer type sizetype.
+     However, we should really return a value of type `size_t',
+     which is just a typedef for an ordinary integer type.  */
+  value = fold_convert_loc (loc, size_type_node, value);
+  return value;
 }
 
 /* Handle C and C++ default attributes.  */
diff --git a/gcc/testsuite/gcc.dg/countof-compile.c b/gcc/testsuite/gcc.dg/countof-compile.c
index afd5659618b..ebbac16ed38 100644
--- a/gcc/testsuite/gcc.dg/countof-compile.c
+++ b/gcc/testsuite/gcc.dg/countof-compile.c
@@ -122,3 +122,9 @@ const_expr(void)
   _Static_assert (_Countof (int [3][n]) == 3);
   _Static_assert (_Countof (int [n][3]) == 7); /* { dg-error "not constant" } */
 }
+
+void
+type(void)
+{
+  _Generic (_Countof (w), __typeof__ (sizeof 0): 0);
+}