; Add commentary to recent changes

* src/image.c (png_load_body):
* src/editfns.c (styled_format):
* src/casefiddle.c (do_casify_multibyte_string):
* src/alloc.c (free_cons): Comment why we use a signed
temporary integer variable.  (Bug#37006)

1 files changed, 2 insertions, 0 deletions

diff --git a/src/casefiddle.c b/src/casefiddle.c
index 6fcb5852141..741973e40af 100644
--- a/src/casefiddle.c
+++ b/src/casefiddle.c
@@ -265,6 +265,8 @@ do_casify_multibyte_string (struct casing_context *ctx, Lisp_Object obj)
 
   ptrdiff_t size = SCHARS (obj), n;
   USE_SAFE_ALLOCA;
+  /* Use a temporary signed variable, since otherwise INT_ADD_WRAPV
+     might incorrectly return non-zero.  */
   ptrdiff_t casing_str_buf_size = sizeof (struct casing_str_buf);
   if (INT_MULTIPLY_WRAPV (size, MAX_MULTIBYTE_LENGTH, &n)
       || INT_ADD_WRAPV (n, casing_str_buf_size, &n))