[Bug c++/84639] gcc/c-family/c-attribs.c:1822:27: runtime error: shift exponent -1 is negative

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84639

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Can be fixed by moving the checking a bit above:

--- a/gcc/c-family/c-attribs.c
+++ b/gcc/c-family/c-attribs.c
@@ -1818,6 +1818,13 @@ common_handle_aligned_attribute (tree *node, tree name,
tree args, int flags,
   /* Log2 of specified alignment.  */
   int pow2align = check_user_alignment (align_expr, true);

+  if (pow2align == -1
+      || !check_cxx_fundamental_alignment_constraints (*node, pow2align,
flags))
+    {
+      *no_add_attrs = true;
+      return NULL_TREE;
+    }
+
   /* The alignment in bits corresponding to the specified alignment.  */
   unsigned bitalign = (1U << pow2align) * BITS_PER_UNIT;

@@ -1826,10 +1833,7 @@ common_handle_aligned_attribute (tree *node, tree name,
tree args, int flags,
   unsigned curalign = 0;
   unsigned lastalign = 0;

-  if (pow2align == -1
-      || !check_cxx_fundamental_alignment_constraints (*node, pow2align,
flags))
-    *no_add_attrs = true;
-  else if (is_type)
+  if (is_type)
     {
       if ((flags & (int) ATTR_FLAG_TYPE_IN_PLACE))
    /* OK, modify the type in place.  */;