[pushed] c++: missing dtor with -fno-elide-constructors [PR100838]

Jason Merrill jason@redhat.com
Wed Jun 2 18:41:45 GMT 2021


tf_no_cleanup only applies to the outermost TARGET_EXPR, and we already
clear it for nested calls in build_over_call, but in this case both
constructor calls came from convert_like, so we need to clear it in the
recursive call as well.  This revealed that we were adding an extra
ck_rvalue in direct-initialization cases where it was wrong.

Tested x86_64-pc-linux-gnu, applying to trunk.

	PR c++/100838

gcc/cp/ChangeLog:

	* call.c (convert_like_internal): Clear tf_no_cleanup when
	recursing.
	(build_user_type_conversion_1): Only add ck_rvalue if
	LOOKUP_ONLYCONVERTING.

gcc/testsuite/ChangeLog:

	* g++.dg/init/no-elide2.C: New test.
---
 gcc/cp/call.c                         |  6 +++--
 gcc/testsuite/g++.dg/init/no-elide2.C | 32 +++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/init/no-elide2.C

diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index 90192b1b8aa..17fc60cd4af 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -4110,7 +4110,7 @@ build_user_type_conversion_1 (tree totype, tree expr, int flags,
 	{
 	  cand->second_conv = build_identity_conv (totype, NULL_TREE);
 
-	  /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
+	  /* If totype isn't a reference, and LOOKUP_ONLYCONVERTING is
 	     set, then this is copy-initialization.  In that case, "The
 	     result of the call is then used to direct-initialize the
 	     object that is the destination of the copy-initialization."
@@ -4119,6 +4119,8 @@ build_user_type_conversion_1 (tree totype, tree expr, int flags,
 	     We represent this in the conversion sequence with an
 	     rvalue conversion, which means a constructor call.  */
 	  if (!TYPE_REF_P (totype)
+	      && cxx_dialect < cxx17
+	      && (flags & LOOKUP_ONLYCONVERTING)
 	      && !(convflags & LOOKUP_NO_TEMP_BIND))
 	    cand->second_conv
 	      = build_conv (ck_rvalue, totype, cand->second_conv);
@@ -7800,7 +7802,7 @@ convert_like_internal (conversion *convs, tree expr, tree fn, int argnum,
   expr = convert_like (next_conversion (convs), expr, fn, argnum,
 		       convs->kind == ck_ref_bind
 		       ? issue_conversion_warnings : false,
-		       c_cast_p, complain);
+		       c_cast_p, complain & ~tf_no_cleanup);
   if (expr == error_mark_node)
     return error_mark_node;
 
diff --git a/gcc/testsuite/g++.dg/init/no-elide2.C b/gcc/testsuite/g++.dg/init/no-elide2.C
new file mode 100644
index 00000000000..9a0ba1936ab
--- /dev/null
+++ b/gcc/testsuite/g++.dg/init/no-elide2.C
@@ -0,0 +1,32 @@
+// PR c++/100838
+// { dg-do run }
+// { dg-additional-options -fno-elide-constructors }
+
+extern "C" int puts (const char *);
+
+int c,d;
+class MyString {
+public:
+  MyString(const char* s = "") {
+    puts ("ctor");
+    ++c;
+  }
+  ~MyString() {
+    puts ("dtor");
+    ++d;
+  }
+  MyString(const MyString& s) {
+    puts ("copy ctor");
+    ++c;
+  }
+  MyString& operator=(const MyString& s);
+};
+
+int main() {
+  {
+    MyString s1 = "Hello";
+    puts ("main");
+  }
+  if (c != d)
+    __builtin_abort();
+}

base-commit: 659cc7d6320aae7ab390b5886f0efed22f78e244
-- 
2.27.0



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