[C++ Patch] PR 88969 ("[9 Regression] ICE in build_op_delete_call, at cp/call.c:6509")

[Paolo Carlini]

Hi,

as far as I can see this ICE on invalid points to a substantive, if 
minor, weakness of our implementation of the destroying operator delete 
facility: we aren't implementing the bits, per 7.6.2.5/(10.1), about 
destroying operator delete having precedence over any other operator 
delete. Thus the below, which is the most straightforward implementation 
I have been able to figure out given the current infrastructure. Tested 
x86_64-linux.

Thanks, Paolo.

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-------------- next part --------------
/cp
2019-01-24  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/88969
	* call.c (build_op_delete_call): Implement 7.6.2.5/(10.1).

/testsuite
2019-01-24  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/88969
	* g++.dg/cpp2a/destroying-delete2.C: New.
-------------- next part --------------
Index: cp/call.c
===================================================================
--- cp/call.c	(revision 268234)
+++ cp/call.c	(working copy)
@@ -6461,6 +6461,19 @@ build_op_delete_call (enum tree_code code, tree ad
 		continue;
 	      }
 
+	    /* -- If any of the deallocation functions is a destroying
+	       operator delete, all deallocation functions that are not
+	       destroying operator deletes are eliminated from further
+	       consideration.  */
+	    bool fn_destroying = destroying_delete_p (fn);
+	    bool elt_destroying = destroying_delete_p (elt);
+	    if (elt_destroying != fn_destroying)
+	      {
+		if (elt_destroying)
+		  fn = elt;
+		continue;
+	      }
+
 	    /* -- If the type has new-extended alignment, a function with a
 	       parameter of type std::align_val_t is preferred; otherwise a
 	       function without such a parameter is preferred. If exactly one
Index: testsuite/g++.dg/cpp2a/destroying-delete2.C
===================================================================
--- testsuite/g++.dg/cpp2a/destroying-delete2.C	(nonexistent)
+++ testsuite/g++.dg/cpp2a/destroying-delete2.C	(working copy)
@@ -0,0 +1,20 @@
+// PR c++/88969
+// { dg-do compile { target c++2a } }
+
+#include <new>
+
+namespace delete_selection_d {
+  struct B {
+    void operator delete(void*) = delete;
+    void operator delete(B *, std::destroying_delete_t) = delete;  // { dg-message "declared here" }
+  };
+  void delete_B(B *b) { delete b; }  // { dg-error "use of deleted function" }
+}
+
+namespace delete_selection_r {
+  struct B {
+    void operator delete(B *, std::destroying_delete_t) = delete;  // { dg-message "declared here" }
+    void operator delete(void*) = delete;
+  };
+  void delete_B(B *b) { delete b; }  // { dg-error "use of deleted function" }
+}