[gcc r13-3009] c++: loop through array CONSTRUCTOR

[gcc r13-3009] c++: loop through array CONSTRUCTOR

[Jason Merrill]

https://gcc.gnu.org/g:dd9c8f644f0f1ac2000108ac369b991664946304

commit r13-3009-gdd9c8f644f0f1ac2000108ac369b991664946304
Author: Jason Merrill <jason@redhat.com>
Date:   Tue Sep 20 16:06:26 2022 -0400

    c++: loop through array CONSTRUCTOR
    
    I noticed that we were ignoring all the special rules for when to use a
    simple INIT_EXPR for array initialization from a CONSTRUCTOR, because
    split_nonconstant_init_1 was also passing 1 to the from_array parameter.
    Arguably that's the real bug, but I think we can be flexible.
    
    The test that I noticed this with no longer fails without it.
    
    gcc/cp/ChangeLog:
    
            * init.cc (build_vec_init): Clear from_array for CONSTRUCTOR
            initializer.

Diff:
---
 gcc/cp/init.cc | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/gcc/cp/init.cc b/gcc/cp/init.cc
index a85c3032130..bf46578c08b 100644
--- a/gcc/cp/init.cc
+++ b/gcc/cp/init.cc
@@ -4394,6 +4394,10 @@ build_vec_init (tree base, tree maxindex, tree init,
 	}
     }
 
+  /* from_array doesn't apply to initialization from CONSTRUCTOR.  */
+  if (init && TREE_CODE (init) == CONSTRUCTOR)
+    from_array = 0;
+
   /* If we have a braced-init-list or string constant, make sure that the array
      is big enough for all the initializers.  */
   bool length_check = (init
@@ -4493,7 +4497,7 @@ build_vec_init (tree base, tree maxindex, tree init,
   /* If initializing one array from another, initialize element by
      element.  We rely upon the below calls to do the argument
      checking.  Evaluate the initializer before entering the try block.  */
-  if (from_array && init && TREE_CODE (init) != CONSTRUCTOR)
+  if (from_array)
     {
       if (lvalue_kind (init) & clk_rvalueref)
 	xvalue = true;