c++: Fix range for with PMFs [PR118923]

The following testcases segfault because the new range for -frange-for-ext-temps
temporary extension extends even the internal TARGET_EXPRs created by
get_member_function_from_ptrfunc.

The following patch fixes that by using get_internal_target_expr for those
instead of force_target_expr (similarly in cp_finish_decl and
build_comparison_op) and using force_target_expr inside of
get_internal_target_expr.

2025-02-25  Jakub Jelinek  <jakub@redhat.com>

	PR c++/118923
	* tree.cc (get_internal_target_expr): Use force_target_expr
	instead of build_target_expr_with_type.
	* typeck.cc (get_member_function_from_ptrfunc): Use
	get_internal_target_expr instead of force_target_expr.
	* decl.cc (cp_finish_decl): Likewise.
	* method.cc (build_comparison_op): Likewise.

	* g++.dg/cpp0x/pr118923.C: New test.
	* g++.dg/cpp1y/pr118923.C: New test.

6 files changed, 110 insertions, 11 deletions

diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 05ad9bb..936e48e 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -9377,8 +9377,7 @@ cp_finish_decl (tree decl, tree init, bool init_const_expr_p,
 	      tree guard = NULL_TREE;
 	      if (cleanups || cleanup)
 		{
-		  guard = force_target_expr (boolean_type_node,
-					     boolean_false_node, tf_none);
+		  guard = get_internal_target_expr (boolean_false_node);
 		  add_stmt (guard);
 		  guard = TARGET_EXPR_SLOT (guard);
 		}
@@ -9407,8 +9406,7 @@ cp_finish_decl (tree decl, tree init, bool init_const_expr_p,
 		     popped that all, so push those extra cleanups around
 		     the whole sequence with a guard variable.  */
 		  gcc_assert (TREE_CODE (sl) == STATEMENT_LIST);
-		  guard = force_target_expr (integer_type_node,
-					     integer_zero_node, tf_none);
+		  guard = get_internal_target_expr (integer_zero_node);
 		  add_stmt (guard);
 		  guard = TARGET_EXPR_SLOT (guard);
 		  for (unsigned i = 0; i < n_extra_cleanups; ++i)
diff --git a/gcc/cp/method.cc b/gcc/cp/method.cc
index 3914bbb..05c19cf 100644
--- a/gcc/cp/method.cc
+++ b/gcc/cp/method.cc
@@ -1597,7 +1597,7 @@ build_comparison_op (tree fndecl, bool defining, tsubst_flags_t complain)
 	      /* Some other array, will need runtime loop.  */
 	      else
 		{
-		  idx = force_target_expr (sizetype, maxval, complain);
+		  idx = get_internal_target_expr (maxval);
 		  loop_indexes = tree_cons (idx, NULL_TREE, loop_indexes);
 		}
 	      expr_type = TREE_TYPE (expr_type);
diff --git a/gcc/cp/tree.cc b/gcc/cp/tree.cc
index 5628a57..5863b68 100644
--- a/gcc/cp/tree.cc
+++ b/gcc/cp/tree.cc
@@ -982,8 +982,7 @@ tree
 get_internal_target_expr (tree init)
 {
   init = convert_bitfield_to_declared_type (init);
-  tree t = build_target_expr_with_type (init, TREE_TYPE (init),
-					tf_warning_or_error);
+  tree t = force_target_expr (TREE_TYPE (init), init, tf_warning_or_error);
   TARGET_EXPR_INTERNAL_P (t) = true;
   return t;
 }
diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc
index a9c32ff..bbaca96 100644
--- a/gcc/cp/typeck.cc
+++ b/gcc/cp/typeck.cc
@@ -4219,16 +4219,14 @@ get_member_function_from_ptrfunc (tree *instance_ptrptr, tree function,
 	      && !DECL_P (instance_ptr)
 	      && !TREE_CONSTANT (instance_ptr)))
 	instance_ptr = instance_save_expr
-	  = force_target_expr (TREE_TYPE (instance_ptr), instance_ptr,
-			       complain);
+	  = get_internal_target_expr (instance_ptr);
 
       /* See above comment.  */
       if (TREE_SIDE_EFFECTS (function)
 	  || (!nonvirtual
 	      && !DECL_P (function)
 	      && !TREE_CONSTANT (function)))
-	function
-	  = force_target_expr (TREE_TYPE (function), function, complain);
+	function = get_internal_target_expr (function);
 
       /* Start by extracting all the information from the PMF itself.  */
       e3 = pfn_from_ptrmemfunc (function);
diff --git a/gcc/testsuite/g++.dg/cpp0x/pr118923.C b/gcc/testsuite/g++.dg/cpp0x/pr118923.C
new file mode 100644
index 0000000..55d3052
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/pr118923.C
@@ -0,0 +1,66 @@
+// PR c++/118923
+// { dg-do run { target c++11 } }
+// { dg-additional-options "-frange-for-ext-temps" { target c++23 } }
+// { dg-additional-options "-fno-range-for-ext-temps" { target c++20_down } }
+
+int g;
+
+struct A {
+  int a[3];
+  A (int x, int y, int z) : a{x, y, z} { if ((g++ & 7) != 4) __builtin_abort (); }
+  A (const A &x) = delete;
+  ~A () { if ((g++ & 7) != 7 - 2 * (__cpp_range_based_for >= 202211)) __builtin_abort (); }
+  int *begin () { return a; }
+  int *end () { return a + 3; }
+};
+
+struct B {
+  B () { if ((g++ & 7) != 3) __builtin_abort (); }
+  B (const B &) = delete;
+  ~B () { if ((g++ & 7) != 5 + (__cpp_range_based_for >= 202211)) __builtin_abort (); }
+};
+
+struct C {
+  A foo (const B &) { return { 1, 2, 3 }; }
+  A bar (const B &) { return { 4, 5, 6 }; }
+  bool baz () { return b; }
+  bool b = false;
+  static C c;
+};
+
+C C::c;
+
+struct D {
+  D () { if ((g++ & 5) != 0) __builtin_abort (); }
+  D (const D &) = delete;
+  ~D () { if ((g & 7) != 1 && (g & 7) != 6 + (__cpp_range_based_for >= 202211)) __builtin_abort (); g++; }
+};
+
+inline C *
+qux (const D &)
+{
+  return &C::c;
+}
+
+void 
+foo ()
+{
+  int z = 1;
+  auto d = qux (D {})->baz () ? &C::bar : &C::foo;
+  for (const int &r : (qux (D {})->*d) (B {}))
+    if (z++ != r)
+      __builtin_abort ();
+  C::c.b = true;
+  d = qux (D {})->baz () ? &C::bar : &C::foo;
+  for (const int &r : (qux (D {})->*d) (B {}))
+    if (z++ != r)
+      __builtin_abort ();
+}
+
+int
+main ()
+{
+  foo ();
+  if (g != 16)
+    __builtin_abort ();
+}
diff --git a/gcc/testsuite/g++.dg/cpp1y/pr118923.C b/gcc/testsuite/g++.dg/cpp1y/pr118923.C
new file mode 100644
index 0000000..b375f47
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/pr118923.C
@@ -0,0 +1,38 @@
+// PR c++/118923
+// { dg-do run { target c++14 } }
+
+struct A {
+  int a[3] = { 0, 0, 0 };
+  int *begin () { return a; }
+  int *end () { return a + 3; }
+};
+
+struct B {
+  A foo () { return { 1, 2, 3 }; }
+  A bar () { return { 1, 2, 3 }; }
+  bool baz () { return b; }
+  bool b = false;
+  static B c;
+};
+
+B B::c;
+
+inline B *
+qux ()
+{
+  return &B::c;
+}
+
+void 
+foo ()
+{
+  auto d = qux ()->baz () ? &B::foo : &B::bar;
+  for (const int &r : (qux ()->*d) ())
+    ;
+}
+
+int
+main ()
+{
+  foo ();
+}