[Bug lto/119792] [14 Regression] internal error with simple discriminated types in Ada

[uecker at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119792

--- Comment #13 from uecker at gcc dot gnu.org ---

FWIW, when I restore my patch on GCC-14 and add the size check to
useless_type_conversion_p, this then fixes the Ada test case. 

diff --git a/gcc/gimple-expr.cc b/gcc/gimple-expr.cc
index 0477c9d5f44..79ac3d35350 100644
--- a/gcc/gimple-expr.cc
+++ b/gcc/gimple-expr.cc
@@ -283,7 +283,11 @@ useless_type_conversion_p (tree outer_type, tree
inner_type)
   else if (AGGREGATE_TYPE_P (inner_type)
           && TREE_CODE (inner_type) == TREE_CODE (outer_type))
     return TYPE_CANONICAL (inner_type)
-          && TYPE_CANONICAL (inner_type) == TYPE_CANONICAL (outer_type);
+          && TYPE_CANONICAL (inner_type) == TYPE_CANONICAL (outer_type)
+          && TREE_CODE (TYPE_SIZE (inner_type)) == INTEGER_CST
+          && TREE_CODE (TYPE_SIZE (outer_type)) == INTEGER_CST
+          && tree_int_cst_equal (TYPE_SIZE (outer_type),
+                                 TYPE_SIZE (inner_type));