c++: Revert unnecessary parts of fix for [PR90996]

The process_init_constructor_array part of my PR90996 patch turns out to
be neither necessary nor sufficient to make the pr90996.C testcase work,
and I wasn't able to come up with a testcase that demonstrates this part
is ever necessary.

gcc/cp/ChangeLog:

	Revert:

	2020-04-07  Patrick Palka  <ppalka@redhat.com>

	PR c++/90996
	* typeck2.c (process_init_constructor_array): Propagate
	CONSTRUCTOR_PLACEHOLDER_BOUNDARY up from each element
	initializer to the array initializer.

gcc/testsuite/ChangeLog:

	PR c++/90996
	* g++.dg/cpp1y/pr90996.C: Turn into execution test to verify
	that each PLACEHOLDER_EXPR gets correctly resolved.

4 files changed, 35 insertions, 19 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 732be07..acd2d7b 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,14 @@
+2020-05-15  Patrick Palka  <ppalka@redhat.com>
+
+	Revert:
+
+	2020-04-07  Patrick Palka  <ppalka@redhat.com>
+
+	PR c++/90996
+	* typeck2.c (process_init_constructor_array): Propagate
+	CONSTRUCTOR_PLACEHOLDER_BOUNDARY up from each element initializer to
+	the array initializer.
+
 2020-05-15  Jason Merrill  <jason@redhat.com>
 
 	PR c++/93286 - ICE with __is_constructible and variadic template.
diff --git a/gcc/cp/typeck2.c b/gcc/cp/typeck2.c
index af84c25..5fd3b82 100644
--- a/gcc/cp/typeck2.c
+++ b/gcc/cp/typeck2.c
@@ -1496,17 +1496,6 @@ process_init_constructor_array (tree type, tree init, int nested, int flags,
 	= massage_init_elt (TREE_TYPE (type), ce->value, nested, flags,
 			    complain);
 
-      if (TREE_CODE (ce->value) == CONSTRUCTOR
-	  && CONSTRUCTOR_PLACEHOLDER_BOUNDARY (ce->value))
-	{
-	  /* Shift CONSTRUCTOR_PLACEHOLDER_BOUNDARY from the element initializer
-	     up to the array initializer, so that the call to
-	     replace_placeholders from store_init_value can resolve any
-	     PLACEHOLDER_EXPRs inside this element initializer.  */
-	  CONSTRUCTOR_PLACEHOLDER_BOUNDARY (ce->value) = 0;
-	  CONSTRUCTOR_PLACEHOLDER_BOUNDARY (init) = 1;
-	}
-
       gcc_checking_assert
 	(ce->value == error_mark_node
 	 || (same_type_ignoring_top_level_qualifiers_p
@@ -1535,13 +1524,6 @@ process_init_constructor_array (tree type, tree init, int nested, int flags,
 	      /* The default zero-initialization is fine for us; don't
 		 add anything to the CONSTRUCTOR.  */
 	      next = NULL_TREE;
-	    else if (TREE_CODE (next) == CONSTRUCTOR
-		     && CONSTRUCTOR_PLACEHOLDER_BOUNDARY (next))
-	      {
-		/* As above.  */
-		CONSTRUCTOR_PLACEHOLDER_BOUNDARY (next) = 0;
-		CONSTRUCTOR_PLACEHOLDER_BOUNDARY (init) = 1;
-	      }
 	  }
 	else if (!zero_init_p (TREE_TYPE (type)))
 	  next = build_zero_init (TREE_TYPE (type),
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 61b2f9e..0a77dbd 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2020-05-15  Patrick Palka  <ppalka@redhat.com>
+
+	PR c++/90996
+	* g++.dg/cpp1y/pr90996.C: Turn into execution test to verify that each
+	PLACEHOLDER_EXPR gets correctly resolved.
+
 2020-05-15  Tobias Burnus  <tobias@codesourcery.com>
 
 	PR fortran/94690
diff --git a/gcc/testsuite/g++.dg/cpp1y/pr90996.C b/gcc/testsuite/g++.dg/cpp1y/pr90996.C
index 780cbb4..eff5b62 100644
--- a/gcc/testsuite/g++.dg/cpp1y/pr90996.C
+++ b/gcc/testsuite/g++.dg/cpp1y/pr90996.C
@@ -1,5 +1,5 @@
 // PR c++/90996
-// { dg-do compile { target c++14 } }
+// { dg-do run { target c++14 } }
 
 struct S
 {
@@ -15,3 +15,20 @@ struct T
 };
 
 T d {};
+
+int
+main()
+{
+  if (++c[0][0].b[0] != 6
+      || ++c[0][1].b[0] != 3
+      || ++c[1][0].b[0] != 3
+      || ++c[1][1].b[0] != 3)
+    __builtin_abort();
+
+  auto& e = d.c;
+  if (++e[0][0].b[0] != 8
+      || ++e[0][1].b[0] != 3
+      || ++e[1][0].b[0] != 3
+      || ++e[1][1].b[0] != 3)
+    __builtin_abort();
+}