c++: Fix up maybe_init_list_as_array for RAW_DATA_CST [PR118124]

The previous patch made me look around some more and I found
maybe_init_list_as_array doesn't handle RAW_DATA_CSTs correctly either,
while the RAW_DATA_CST is properly split during finish_compound_literal,
it was using CONSTRUCTOR_NELTS as the size of the arrays, which is wrong,
RAW_DATA_CST could stand for far more initializers.

2025-01-15  Jakub Jelinek  <jakub@redhat.com>

	PR c++/118124
	* cp-tree.h (build_array_of_n_type): Change second argument type
	from int to unsigned HOST_WIDE_INT.
	* tree.cc (build_array_of_n_type): Likewise.
	* call.cc (count_ctor_elements): New function.
	(maybe_init_list_as_array): Use it instead of CONSTRUCTOR_NELTS.
	(convert_like_internal): Use length from init's type instead of
	len when handling the maybe_init_list_as_array case.

	* g++.dg/cpp0x/initlist-opt5.C: New test.

1 files changed, 23 insertions, 0 deletions

diff --git a/gcc/testsuite/g++.dg/cpp0x/initlist-opt5.C b/gcc/testsuite/g++.dg/cpp0x/initlist-opt5.C
new file mode 100644
index 0000000..65a1fd6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/initlist-opt5.C
@@ -0,0 +1,23 @@
+// PR c++/118124
+// { dg-do compile { target c++11 } }
+// { dg-options "-O2" }
+
+namespace std {
+template <class T> struct initializer_list {
+private:
+  const T *_M_array;
+  decltype (sizeof 0) _M_len;
+};
+}
+struct B {
+  B (int);
+};
+struct A {
+  A (std::initializer_list<B>);
+};
+A a { 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7,
+      8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
+      0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1,
+      2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3,
+      4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5,
+      6, 7, 8, 9, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1, 2, 3, 4, 5 };