decl.c (gnat_to_gnu_entity): Create a mere scalar constant instead of a reference for renaming of scalar literal.

	* gcc-interface/decl.c (gnat_to_gnu_entity) <object>: Create a mere
	scalar constant instead of a reference for renaming of scalar literal.
	Do not create a new object for constant renaming except for a function
	call.  Make sure a VAR_DECL is created for the renaming pointer.
	* gcc-interface/trans.c (constant_decl_with_initializer_p): New.
	(fold_constant_decl_in_expr): New function.
	(Identifier_to_gnu): Use constant_decl_with_initializer_p.
	For a constant renaming, try to fold a constant DECL in the result.
	(lvalue_required_p) <N_Object_Renaming_Declaration>: Always return 1.
	(Identifier_to_gnu): Reference the renamed object of constant renaming
	pointers directly.
	(Case_Statement_to_gnu): Do not re-fold the bounds of integer types.
	Assert that the case values are constant.
	* gcc-interface/utils.c (invalidate_global_renaming_pointers): Do not
	invalidate constant renaming pointers.

Co-Authored-By: Pierre-Marie de Rodat <derodat@adacore.com>

From-SVN: r209411

1 files changed, 6 insertions, 2 deletions

diff --git a/gcc/ada/gcc-interface/utils.c b/gcc/ada/gcc-interface/utils.c
index 8172f5f..4814f9a 100644
--- a/gcc/ada/gcc-interface/utils.c
+++ b/gcc/ada/gcc-interface/utils.c
@@ -2514,7 +2514,10 @@ record_global_renaming_pointer (tree decl)
   vec_safe_push (global_renaming_pointers, decl);
 }
 
-/* Invalidate the global renaming pointers.   */
+/* Invalidate the global renaming pointers that are not constant, lest their
+   renamed object contains SAVE_EXPRs tied to an elaboration routine.  Note
+   that we should not blindly invalidate everything here because of the need
+   to propagate constant values through renaming.  */
 
 void
 invalidate_global_renaming_pointers (void)
@@ -2526,7 +2529,8 @@ invalidate_global_renaming_pointers (void)
     return;
 
   FOR_EACH_VEC_ELT (*global_renaming_pointers, i, iter)
-    SET_DECL_RENAMED_OBJECT (iter, NULL_TREE);
+    if (!TREE_CONSTANT (DECL_RENAMED_OBJECT (iter)))
+      SET_DECL_RENAMED_OBJECT (iter, NULL_TREE);
 
   vec_free (global_renaming_pointers);
 }