[Bug tree-optimization/81814] Incorrect behaviour at -O0 (conditional operator)

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81814

--- Comment #8 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
I wonder if I could just

--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -3401,14 +3401,14 @@ operand_equal_for_comparison_p (tree arg0, tree arg1,
tree other)

   primarg1 = get_narrower (arg1, &unsignedp1);
   primother = get_narrower (other, &unsignedpo);
+  tree type = TREE_TYPE (arg0);

   correct_width = TYPE_PRECISION (TREE_TYPE (arg1));
   if (unsignedp1 == unsignedpo
+      && TYPE_PRECISION (TREE_TYPE (primarg1)) == TYPE_PRECISION (type)
       && TYPE_PRECISION (TREE_TYPE (primarg1)) < correct_width
       && TYPE_PRECISION (TREE_TYPE (primother)) < correct_width)
     {
-      tree type = TREE_TYPE (arg0);
-
       /* Make sure shorter operand is extended the right way
     to match the longer operand.  */
       primarg1 = fold_convert (signed_or_unsigned_type_for

so far it seems to work.