On 4/10/20 11:17 AM, Jakub Jelinek wrote:
On Fri, Apr 10, 2020 at 10:29:29AM +0200, Martin Liška wrote:
+/* Valid pairs of new and delete operators for DCE. */
+static hash_set<nofree_string_hash> *valid_pairs = NULL;
+
+/* Return that NEW_CALL and DELETE_CALL are a valid pair of new
+ and delete operators. */
+
+static bool
+valid_new_delete_pair_p (gimple *new_call, gimple *delete_call)
+{
+ const char *new_name
+ = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (gimple_call_fndecl (new_call)));
+ const char *delete_name
+ = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (gimple_call_fndecl
(delete_call)));
+
+ if (new_name[0] == '_' and new_name[1] == '_')
+ ++new_name;
+ if (delete_name[0] == '_' and delete_name[1] == '_')
+ ++delete_name;
+
+ char *needle = concat (new_name, ":", delete_name, NULL);
+
+ if (valid_pairs == NULL)
+ {
+ valid_pairs = new hash_set<nofree_string_hash> ();
+ /* Invalid pairs:
+ non-[] and []
+ aligned and non-aligned
+ */
+
+ const char *pairs[] = {
+ /* non-[] operators. */
+ "_Znwm:_ZdlPv" ,
+ "_Znwm:_ZdlPvm" ,
Formatting, I think the /* and "_Z should be two columns from const char,
and no space before ,
Not sure I like using the : and using a hash table looks like an overkill to
me, don't we have only 8 options, and most of them with different identifier
lengths? The concat itself will take a while...
And, what's worse, the m in there is really different on different targets.
It can be j, m or y depending on what fundamental type size_t is.
So why not (completely untested):
Hi.
I've updated a bit the Jakub's patch.
Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
Ready to be installed?
Thanks,
Martin
static bool
valid_new_delete_pair_p (gimple *new_call, gimple *delete_call)
{
tree new_asm = DECL_ASSEMBLER_NAME (gimple_call_fndecl (new_call));
tree delete_asm = DECL_ASSEMBLER_NAME (gimple_call_fndecl (delete_call));
const char *new_name = IDENTIFIER_POINTER (new_asm);
const char *delete_name = IDENTIFIER_POINTER (delete_asm);
unsigned int new_len = IDENTIFIER_LENGTH (mew_asm);
unsigned int delete_len = IDENTIFIER_LENGTH (delete_asm);
if (new_name < 5 || delete_len < 6)
return false;
if (new_name[0] == '_')
++new_name, --new_len;
if (new_name[0] == '_')
++new_name, --new_len;
if (delete_name[0] == '_')
++delete_name, --delete_len;
if (delete_name[0] == '_')
++delete_name, --delete_len;
if (new_len < 4 || delete_len < 5)
return false;
/* *_len is now just the length after initial underscores. */
if (new_name[0] != 'Z' || new_name[1] != 'n')
return false;
if (delete_name[0] != 'Z' || delete_name[1] != 'd')
return false;
/* _Znw must match _Zdl, _Zna must match _Zda. */
if ((new_name[2] != 'w' || delete_name[2] != 'l')
&& (new_name[2] != 'a' || delete_name[2] != 'a'))
return false;
if (new_name[3] != 'j' && new_name[3] != 'm' && new_name[3] != 'y')
return false;
if (delete_name[3] != 'P' || delete_name[4] != 'v')
return false;
if (new_len == 4
|| (new_len == 18 && !memcmp (new_name + 4, "RKSt9nothrow_t", 14)))
{
/* _ZnXY or _ZnXYRKSt9nothrow_t matches
_ZdXPv, _ZdXPvY and _ZdXPvRKSt9nothrow_t. */
if (delete_len == 5)
return true;
if (delete_len == 6 && delete_name[5] == new_name[3])
return true;
if (delete_len == 19 && !memcmp (delete_name + 5, "RKSt9nothrow_t", 14))
return true;
}
else if ((new_len == 19 && !memcmp (new_name + 4, "St11align_val_t", 15))
|| (new_len == 33
&& !memcmp (new_name + 4, "St11align_val_tRKSt9nothrow_t", 29)))
{
/* _ZnXYSt11align_val_t or _ZnXYSt11align_val_tRKSt9nothrow_t matches
_ZdXPvSt11align_val_t or _ZdXPvYSt11align_val_t or or
_ZdXPvSt11align_val_tRKSt9nothrow_t. */
if (delete_len == 20 && !memcmp (delete_name + 5, "St11align_val_t", 15))
return true;
if (delete_len == 21
&& delete_name[5] == new_name[3]
&& !memcmp (delete_name + 6, "St11align_val_t", 15))
return true;
if (delete_len == 34
&& !memcmp (delete_name + 5, "St11align_val_tRKSt9nothrow_t", 29))
return true;
}
return false;
}
Jakub
>From 60626d4b040bc502c563b7c014b62751a517705a Mon Sep 17 00:00:00 2001
From: Martin Liska <mli...@suse.cz>
Date: Thu, 9 Apr 2020 15:50:58 +0200
Subject: [PATCH] List valid pairs for new and delete operators.
gcc/ChangeLog:
2020-04-09 Martin Liska <mli...@suse.cz>
Jakub Jelinek <ja...@redhat.com>
PR c++/94314
* cgraphclones.c (set_new_clone_decl_and_node_flags): Drop
DECL_IS_REPLACEABLE_OPERATOR during cloning.
* tree-ssa-dce.c (valid_new_delete_pair_p): New function.
(propagate_necessity): Check operator names.
(perform_tree_ssa_dce): Delete valid_pairs.
gcc/testsuite/ChangeLog:
2020-04-09 Martin Liska <mli...@suse.cz>
Jakub Jelinek <ja...@redhat.com>
PR c++/94314
* g++.dg/pr94314-4.C: New test.
---
gcc/cgraphclones.c | 2 +
gcc/testsuite/g++.dg/pr94314-4.C | 33 ++++++++++
gcc/tree-ssa-dce.c | 103 ++++++++++++++++++++++++++++---
3 files changed, 128 insertions(+), 10 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/pr94314-4.C
diff --git a/gcc/cgraphclones.c b/gcc/cgraphclones.c
index c73b8f810f0..8f541a28b6e 100644
--- a/gcc/cgraphclones.c
+++ b/gcc/cgraphclones.c
@@ -165,6 +165,7 @@ set_new_clone_decl_and_node_flags (cgraph_node *new_node)
DECL_STATIC_DESTRUCTOR (new_node->decl) = 0;
DECL_SET_IS_OPERATOR_NEW (new_node->decl, 0);
DECL_SET_IS_OPERATOR_DELETE (new_node->decl, 0);
+ DECL_IS_REPLACEABLE_OPERATOR (new_node->decl) = 0;
new_node->externally_visible = 0;
new_node->local = 1;
@@ -1030,6 +1031,7 @@ cgraph_node::create_version_clone_with_body
DECL_STATIC_DESTRUCTOR (new_decl) = 0;
DECL_SET_IS_OPERATOR_NEW (new_decl, 0);
DECL_SET_IS_OPERATOR_DELETE (new_decl, 0);
+ DECL_IS_REPLACEABLE_OPERATOR (new_decl) = 0;
/* Create the new version's call-graph node.
and update the edges of the new node. */
diff --git a/gcc/testsuite/g++.dg/pr94314-4.C b/gcc/testsuite/g++.dg/pr94314-4.C
new file mode 100644
index 00000000000..afa2a443dc4
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr94314-4.C
@@ -0,0 +1,33 @@
+/* PR c++/94314. */
+/* { dg-do run } */
+/* { dg-options "-O2 -fdump-tree-cddce-details -std=c++14" } */
+/* { dg-additional-options "-fdelete-null-pointer-checks" } */
+
+#include <stdio.h>
+
+int count = 0;
+
+__attribute__((malloc, noinline)) void* operator new[](__SIZE_TYPE__ sz) {
+ ++count;
+ return ::operator new(sz);
+}
+
+void operator delete[](void* ptr) noexcept {
+ --count;
+ ::operator delete(ptr);
+}
+
+void operator delete[](void* ptr, __SIZE_TYPE__ sz) noexcept {
+ --count;
+ ::operator delete(ptr, sz);
+}
+
+int main() {
+ delete[] new int[1];
+ if (count != 0)
+ __builtin_abort ();
+
+ return 0;
+}
+
+/* { dg-final { scan-tree-dump-not "Deleting : operator delete" "cddce1"} } */
diff --git a/gcc/tree-ssa-dce.c b/gcc/tree-ssa-dce.c
index fd5f24c746c..69566cd50e2 100644
--- a/gcc/tree-ssa-dce.c
+++ b/gcc/tree-ssa-dce.c
@@ -646,6 +646,80 @@ degenerate_phi_p (gimple *phi)
return true;
}
+/* Valid pairs of new and delete operators for DCE. */
+static hash_set<nofree_string_hash> *valid_pairs = NULL;
+
+/* Return that NEW_CALL and DELETE_CALL are a valid pair of new
+ and delete operators. */
+
+static bool
+valid_new_delete_pair_p (gimple *new_call, gimple *delete_call)
+{
+ tree new_asm = DECL_ASSEMBLER_NAME (gimple_call_fndecl (new_call));
+ tree delete_asm = DECL_ASSEMBLER_NAME (gimple_call_fndecl (delete_call));
+ const char *new_name = IDENTIFIER_POINTER (new_asm);
+ const char *delete_name = IDENTIFIER_POINTER (delete_asm);
+ unsigned int new_len = IDENTIFIER_LENGTH (new_asm);
+ unsigned int delete_len = IDENTIFIER_LENGTH (delete_asm);
+
+ if (new_len < 5 || delete_len < 6)
+ return false;
+ if (new_name[0] == '_')
+ ++new_name, --new_len;
+ if (new_name[0] == '_')
+ ++new_name, --new_len;
+ if (delete_name[0] == '_')
+ ++delete_name, --delete_len;
+ if (delete_name[0] == '_')
+ ++delete_name, --delete_len;
+ if (new_len < 4 || delete_len < 5)
+ return false;
+ /* *_len is now just the length after initial underscores. */
+ if (new_name[0] != 'Z' || new_name[1] != 'n')
+ return false;
+ if (delete_name[0] != 'Z' || delete_name[1] != 'd')
+ return false;
+ /* _Znw must match _Zdl, _Zna must match _Zda. */
+ if ((new_name[2] != 'w' || delete_name[2] != 'l')
+ && (new_name[2] != 'a' || delete_name[2] != 'a'))
+ return false;
+ /* 'j', 'm' and 'y' correspond to size_t. */
+ if (new_name[3] != 'j' && new_name[3] != 'm' && new_name[3] != 'y')
+ return false;
+ if (delete_name[3] != 'P' || delete_name[4] != 'v')
+ return false;
+ if (new_len == 4
+ || (new_len == 18 && !memcmp (new_name + 4, "RKSt9nothrow_t", 14)))
+ {
+ /* _ZnXY or _ZnXYRKSt9nothrow_t matches
+ _ZdXPv, _ZdXPvY and _ZdXPvRKSt9nothrow_t. */
+ if (delete_len == 5)
+ return true;
+ if (delete_len == 6 && delete_name[5] == new_name[3])
+ return true;
+ if (delete_len == 19 && !memcmp (delete_name + 5, "RKSt9nothrow_t", 14))
+ return true;
+ }
+ else if ((new_len == 19 && !memcmp (new_name + 4, "St11align_val_t", 15))
+ || (new_len == 33
+ && !memcmp (new_name + 4, "St11align_val_tRKSt9nothrow_t", 29)))
+ {
+ /* _ZnXYSt11align_val_t or _ZnXYSt11align_val_tRKSt9nothrow_t matches
+ _ZdXPvSt11align_val_t or _ZdXPvYSt11align_val_t or or
+ _ZdXPvSt11align_val_tRKSt9nothrow_t. */
+ if (delete_len == 20 && !memcmp (delete_name + 5, "St11align_val_t", 15))
+ return true;
+ if (delete_len == 21
+ && delete_name[5] == new_name[3]
+ && !memcmp (delete_name + 6, "St11align_val_t", 15))
+ return true;
+ if (delete_len == 34
+ && !memcmp (delete_name + 5, "St11align_val_tRKSt9nothrow_t", 29))
+ return true;
+ }
+ return false;
+}
+
/* Propagate necessity using the operands of necessary statements.
Process the uses on each statement in the worklist, and add all
feeding statements which contribute to the calculation of this
@@ -824,16 +898,23 @@ propagate_necessity (bool aggressive)
|| DECL_FUNCTION_CODE (def_callee) == BUILT_IN_CALLOC))
|| DECL_IS_REPLACEABLE_OPERATOR_NEW_P (def_callee)))
{
- /* Delete operators can have alignment and (or) size as next
- arguments. When being a SSA_NAME, they must be marked
- as necessary. */
- if (is_delete_operator && gimple_call_num_args (stmt) >= 2)
- for (unsigned i = 1; i < gimple_call_num_args (stmt); i++)
- {
- tree arg = gimple_call_arg (stmt, i);
- if (TREE_CODE (arg) == SSA_NAME)
- mark_operand_necessary (arg);
- }
+ if (is_delete_operator)
+ {
+ if (!valid_new_delete_pair_p (def_stmt, stmt))
+ mark_operand_necessary (gimple_call_arg (stmt, 0));
+
+ /* Delete operators can have alignment and (or) size
+ as next arguments. When being a SSA_NAME, they
+ must be marked as necessary. */
+ if (gimple_call_num_args (stmt) >= 2)
+ for (unsigned i = 1; i < gimple_call_num_args (stmt);
+ i++)
+ {
+ tree arg = gimple_call_arg (stmt, i);
+ if (TREE_CODE (arg) == SSA_NAME)
+ mark_operand_necessary (arg);
+ }
+ }
continue;
}
@@ -1662,6 +1743,8 @@ perform_tree_ssa_dce (bool aggressive)
visited = BITMAP_ALLOC (NULL);
propagate_necessity (aggressive);
BITMAP_FREE (visited);
+ delete valid_pairs;
+ valid_pairs = NULL;
something_changed |= eliminate_unnecessary_stmts ();
something_changed |= cfg_altered;
--
2.26.0
