Re: [PATCH] - Devirtualization of array destruction (C++) - 110057

2023-07-25 Thread Jason Merrill via Gcc-patches

On 7/12/23 10:10, Ng YongXiang via Gcc-patches wrote:

Component:
c++

Bug ID:
110057

Bugzilla link:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110057

Description:
Array should not call virtual destructor of object when array is destructed

ChangeLog:

2023-07-12  Ng YongXiang  PR c++
* Devirtualize auto generated destructor calls of arraycp/*
init.c: Call non virtual destructor of objects in arraytestsuite/
   * g++.dg/devirt-array-destructor-1.C: New.*
g++.dg/devirt-array-destructor-2.C: New.


On Wed, Jul 12, 2023 at 5:02 PM Xi Ruoyao  wrote:


On Wed, 2023-07-12 at 16:58 +0800, Ng YongXiang via Gcc-patches wrote:

I'm writing to seek for a review for an issue I filed some time ago.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110057 . A proposed patch

is

attached in the bug tracker as well.


You should send the patch to gcc-patches@gcc.gnu.org for a review, see
https://gcc.gnu.org/contribute.html for the details.  Generally we
consider patches attached in bugzilla as drafts.


Thanks!  The change makes sense under 
https://eel.is/c++draft/expr.delete#3.sentence-2 , but please look again 
at contribute.html.


In particular, the Legal section; you don't seem to have a copyright 
assignment with the FSF, nor do I see a DCO certification 
(https://gcc.gnu.org/dco.html) in your patch.


Like the examples in contribute.html, the subject line should be more 
like "[PATCH] c++: devirtualization of array destruction [PR110057]"


The ChangeLog entry should be in the commit message.


 * g++.dg/warn/pr83054.C: Change expected number of devirtualized calls


This isn't just changing the expected number, it's also changing the 
array from a local variable to dynamically allocated, which is a big 
change to what's being tested.  If you want to test the dynamic case, 
please add a new test instead of making this change.



diff --git a/gcc/testsuite/g++.dg/warn/pr83054.C 
b/gcc/testsuite/g++.dg/warn/pr83054.C
index 5285f94acee..7cd0951713d 100644
--- a/gcc/testsuite/g++.dg/warn/pr83054.C
+++ b/gcc/testsuite/g++.dg/warn/pr83054.C
@@ -10,7 +10,7 @@
 #endif
 
 extern "C" int printf (const char *, ...);

-struct foo // { dg-warning "final would enable devirtualization of 5 calls" }
+struct foo // { dg-warning "final would enable devirtualization of 1 call" }
 {
   static int count;
   void print (int i, int j) { printf ("foo[%d][%d] = %d\n", i, j, x); }
@@ -29,19 +29,15 @@ int foo::count;
 
 int main ()

 {
-  {
-foo array[3][3];
-for (int i = 0; i < 3; i++)
-  {
-   for (int j = 0; j < 3; j++)
- {
-   printf("[%d][%d] = %x\n", i, j, (void *)[i][j]);
- }
-  }
-  // The count should be nine, if not, fail the test.
-  if (foo::count != 9)
-   return 1;
-  }
+  foo* arr[9];
+  for (int i = 0; i < 9; ++i)
+arr[i] = new foo();
+  if (foo::count != 9)
+return 1;
+  for (int i = 0; i < 9; ++i)
+arr[i]->print(i / 3, i % 3);
+  for (int i = 0; i < 9; ++i)
+delete arr[i];





[PATCH] - Devirtualization of array destruction (C++) - 110057

2023-07-12 Thread Ng YongXiang via Gcc-patches
Component:
c++

Bug ID:
110057

Bugzilla link:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110057

Description:
Array should not call virtual destructor of object when array is destructed

ChangeLog:

2023-07-12  Ng YongXiang  PR c++
* Devirtualize auto generated destructor calls of arraycp/*
init.c: Call non virtual destructor of objects in arraytestsuite/
  * g++.dg/devirt-array-destructor-1.C: New.*
g++.dg/devirt-array-destructor-2.C: New.
* g++.dg/warn/pr83054.C: Change expected number of devirtualized calls


On Wed, Jul 12, 2023 at 5:02 PM Xi Ruoyao  wrote:

> On Wed, 2023-07-12 at 16:58 +0800, Ng YongXiang via Gcc-patches wrote:
> > I'm writing to seek for a review for an issue I filed some time ago.
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110057 . A proposed patch
> is
> > attached in the bug tracker as well.
>
> You should send the patch to gcc-patches@gcc.gnu.org for a review, see
> https://gcc.gnu.org/contribute.html for the details.  Generally we
> consider patches attached in bugzilla as drafts.
>
> --
> Xi Ruoyao 
> School of Aerospace Science and Technology, Xidian University
>
From aafa45669695520c26504479eb3f21d61ea81edb Mon Sep 17 00:00:00 2001
From: yongxiangng 
Date: Sat, 3 Jun 2023 00:36:32 +0800
Subject: [PATCH] Devirtualize auto generated destructor calls of arrays

---
 gcc/cp/init.cc|  8 +++---
 .../g++.dg/devirt-array-destructor-1.C| 27 ++
 .../g++.dg/devirt-array-destructor-2.C| 28 +++
 gcc/testsuite/g++.dg/warn/pr83054.C   | 24 +++-
 4 files changed, 69 insertions(+), 18 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/devirt-array-destructor-1.C
 create mode 100644 gcc/testsuite/g++.dg/devirt-array-destructor-2.C

diff --git a/gcc/cp/init.cc b/gcc/cp/init.cc
index 6ccda365b04..69ab51d0a4b 100644
--- a/gcc/cp/init.cc
+++ b/gcc/cp/init.cc
@@ -4112,8 +4112,8 @@ build_vec_delete_1 (location_t loc, tree base, tree maxindex, tree type,
   if (type_build_dtor_call (type))
 	{
 	  tmp = build_delete (loc, ptype, base, sfk_complete_destructor,
-			  LOOKUP_NORMAL|LOOKUP_DESTRUCTOR, 1,
-			  complain);
+			  LOOKUP_NORMAL|LOOKUP_DESTRUCTOR|LOOKUP_NONVIRTUAL,
+			  1, complain);
 	  if (tmp == error_mark_node)
 	return error_mark_node;
 	}
@@ -4143,8 +4143,8 @@ build_vec_delete_1 (location_t loc, tree base, tree maxindex, tree type,
 return error_mark_node;
   body = build_compound_expr (loc, body, tmp);
   tmp = build_delete (loc, ptype, tbase, sfk_complete_destructor,
-		  LOOKUP_NORMAL|LOOKUP_DESTRUCTOR, 1,
-		  complain);
+		  LOOKUP_NORMAL|LOOKUP_DESTRUCTOR|LOOKUP_NONVIRTUAL,
+		  1, complain);
   if (tmp == error_mark_node)
 return error_mark_node;
   body = build_compound_expr (loc, body, tmp);
diff --git a/gcc/testsuite/g++.dg/devirt-array-destructor-1.C b/gcc/testsuite/g++.dg/devirt-array-destructor-1.C
new file mode 100644
index 000..be2d16ae761
--- /dev/null
+++ b/gcc/testsuite/g++.dg/devirt-array-destructor-1.C
@@ -0,0 +1,27 @@
+/* { dg-do run } */
+/* Virtual calls should be devirtualized because we know dynamic type of object in array at compile time */
+/* { dg-options "-O3 -fdump-tree-optimized -fno-inline"  } */
+
+class A
+{
+public:
+  virtual ~A()
+  {
+  }
+};
+
+class B : public A
+{
+public:
+  virtual ~B()
+  {
+  }
+};
+
+int main()
+{
+  B b[10];
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "OBJ_TYPE_REF" 0 "optimized"} } */
diff --git a/gcc/testsuite/g++.dg/devirt-array-destructor-2.C b/gcc/testsuite/g++.dg/devirt-array-destructor-2.C
new file mode 100644
index 000..0b3ab2ca9d0
--- /dev/null
+++ b/gcc/testsuite/g++.dg/devirt-array-destructor-2.C
@@ -0,0 +1,28 @@
+/* { dg-do run } */
+/* Virtual calls should be devirtualized because we know dynamic type of object in array at compile time */
+/* { dg-options "-O3 -fdump-tree-optimized -fno-inline"  } */
+
+class A
+{
+public:
+  virtual ~A()
+  {
+  }
+};
+
+class B : public A
+{
+public:
+  virtual ~B()
+  {
+  }
+};
+
+int main()
+{
+  B* ptr = new B[10];
+  delete[] ptr;
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "OBJ_TYPE_REF" 0 "optimized"} } */
diff --git a/gcc/testsuite/g++.dg/warn/pr83054.C b/gcc/testsuite/g++.dg/warn/pr83054.C
index 5285f94acee..7cd0951713d 100644
--- a/gcc/testsuite/g++.dg/warn/pr83054.C
+++ b/gcc/testsuite/g++.dg/warn/pr83054.C
@@ -10,7 +10,7 @@
 #endif
 
 extern "C" int printf (const char *, ...);
-struct foo // { dg-warning "final would enable devirtualization of 5 calls" }
+struct foo // { dg-warning "final would enable devirtualization of 1 call" }
 {
   static int count;
   void print (int i, int j) { printf ("foo[%d][%d] = %d\n", i, j, x); }
@@ -29,19 +29,15 @@ int foo::count;
 
 int main ()
 {
-  {
-foo array[3][3];
-for (int i = 0; i < 3; i++)
-  {
-	for (int j = 0; j < 3; j++)
-	  {
-	printf("[%d][%d] = %x\n", i, j, (void