From 508e475706c3560a86b08446e1bb764773b93ed9 Mon Sep 17 00:00:00 2001
From: Jan Hubicka <jh@suse.cz>
Date: Sat, 21 Aug 2010 11:46:15 +0200
Subject: [PATCH] re PR middle-end/45307 (Stores expanding to no RTL not
removed by tree optimizers, Empty ctors/dtors not eliminated)
PR c++/45307
PR c++/17736
* cgraph.h (cgraph_only_called_directly_p,
cgraph_can_remove_if_no_direct_calls_and_refs_p): Handle
static cdtors.
* cgraphunit.c (cgraph_decide_is_function_needed): Static cdtors
are not needed.
(cgraph_finalize_function): Static cdtors are reachable.
(cgraph_mark_functions_to_output): Use cgraph_only_called_directly_p.
* gcc.dg/ipa/ctor-empty-1.c: Add testcase.
* g++.dg/tree-ssa/empty-2.C: Check that constructor got optimized out.
From-SVN: r163439
---
gcc/ChangeLog | 12 +++++++++++
gcc/cgraph.c | 27 +++++++++++++++++++++++++
gcc/cgraph.h | 22 +++++++++-----------
gcc/cgraphunit.c | 12 ++++-------
gcc/testsuite/ChangeLog | 7 +++++++
gcc/testsuite/g++.dg/tree-ssa/empty-2.C | 5 ++++-
gcc/testsuite/gcc.dg/ipa/ctor-empty-1.c | 8 ++++++++
7 files changed, 71 insertions(+), 22 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/ipa/ctor-empty-1.c
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 56fef865fa52..4f467cac8a98 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,15 @@
+2010-08-20 Jan Hubicka <jh@suse.cz>
+
+ PR c++/45307
+ PR c++/17736
+ * cgraph.h (cgraph_only_called_directly_p,
+ cgraph_can_remove_if_no_direct_calls_and_refs_p): Handle
+ static cdtors.
+ * cgraphunit.c (cgraph_decide_is_function_needed): Static cdtors
+ are not needed.
+ (cgraph_finalize_function): Static cdtors are reachable.
+ (cgraph_mark_functions_to_output): Use cgraph_only_called_directly_p.
+
2010-08-20 Jan Hubicka <jh@suse.cz>
* lto-cgraph.c (lto_output_edge): Use gimple_has_body_p instead of flag_wpa.
diff --git a/gcc/cgraph.c b/gcc/cgraph.c
index 32ad190135b2..470fb5a78fb4 100644
--- a/gcc/cgraph.c
+++ b/gcc/cgraph.c
@@ -2709,6 +2709,33 @@ cgraph_edge_cannot_lead_to_return (struct cgraph_edge *e)
return cgraph_node_cannot_return (e->callee);
}
+/* Return true when function NODE can be removed from callgraph
+ if all direct calls are eliminated. */
+
+bool
+cgraph_can_remove_if_no_direct_calls_and_refs_p (struct cgraph_node *node)
+{
+ /* When function is needed, we can not remove it. */
+ if (node->needed || node->reachable_from_other_partition)
+ return false;
+ /* Only COMDAT functions can be removed if externally visible. */
+ if (node->local.externally_visible
+ && (!DECL_COMDAT (node->decl) || node->local.used_from_object_file))
+ return false;
+ /* Constructors and destructors are executed by the runtime, however
+ we can get rid of all pure constructors and destructors. */
+ if (DECL_STATIC_CONSTRUCTOR (node->decl)
+ || DECL_STATIC_DESTRUCTOR (node->decl))
+ {
+ int flags = flags_from_decl_or_type (node->decl);
+ if (!optimize
+ || !(flags & (ECF_CONST | ECF_PURE))
+ || (flags & ECF_LOOPING_CONST_OR_PURE))
+ return false;
+ }
+ return true;
+}
+
/* Return true when function NODE can be excpected to be removed
from program when direct calls in this compilation unit are removed.
diff --git a/gcc/cgraph.h b/gcc/cgraph.h
index 2dcdf2f22f3d..f77a280d12f7 100644
--- a/gcc/cgraph.h
+++ b/gcc/cgraph.h
@@ -608,6 +608,10 @@ void cgraph_set_looping_const_or_pure_flag (struct cgraph_node *, bool);
tree clone_function_name (tree decl, const char *);
bool cgraph_node_cannot_return (struct cgraph_node *);
bool cgraph_edge_cannot_lead_to_return (struct cgraph_edge *);
+bool cgraph_will_be_removed_from_program_if_no_direct_calls
+ (struct cgraph_node *node);
+bool cgraph_can_remove_if_no_direct_calls_and_refs_p
+ (struct cgraph_node *node);
/* In cgraphunit.c */
extern FILE *cgraph_dump_file;
@@ -664,8 +668,6 @@ void cgraph_remove_node_duplication_hook (struct cgraph_2node_hook_list *);
void cgraph_materialize_all_clones (void);
gimple cgraph_redirect_edge_call_stmt_to_callee (struct cgraph_edge *);
bool cgraph_propagate_frequency (struct cgraph_node *node);
-bool cgraph_will_be_removed_from_program_if_no_direct_calls
- (struct cgraph_node *node);
/* In cgraphbuild.c */
unsigned int rebuild_cgraph_edges (void);
void cgraph_rebuild_references (void);
@@ -903,17 +905,11 @@ varpool_node_set_nonempty_p (varpool_node_set set)
static inline bool
cgraph_only_called_directly_p (struct cgraph_node *node)
{
- return !node->needed && !node->address_taken && !node->local.externally_visible;
-}
-
-/* Return true when function NODE can be removed from callgraph
- if all direct calls are eliminated. */
-
-static inline bool
-cgraph_can_remove_if_no_direct_calls_and_refs_p (struct cgraph_node *node)
-{
- return (!node->needed && !node->reachable_from_other_partition
- && (DECL_COMDAT (node->decl) || !node->local.externally_visible));
+ return (!node->needed && !node->address_taken
+ && !node->reachable_from_other_partition
+ && !DECL_STATIC_CONSTRUCTOR (node->decl)
+ && !DECL_STATIC_DESTRUCTOR (node->decl)
+ && !node->local.externally_visible);
}
/* Return true when function NODE can be removed from callgraph
diff --git a/gcc/cgraphunit.c b/gcc/cgraphunit.c
index 4ef63a2d3507..57b7a8d9efa3 100644
--- a/gcc/cgraphunit.c
+++ b/gcc/cgraphunit.c
@@ -367,11 +367,6 @@ cgraph_decide_is_function_needed (struct cgraph_node *node, tree decl)
&& !DECL_COMDAT (decl) && !DECL_EXTERNAL (decl))
return true;
- /* Constructors and destructors are reachable from the runtime by
- some mechanism. */
- if (DECL_STATIC_CONSTRUCTOR (decl) || DECL_STATIC_DESTRUCTOR (decl))
- return true;
-
return false;
}
@@ -532,7 +527,9 @@ cgraph_finalize_function (tree decl, bool nested)
/* Since we reclaim unreachable nodes at the end of every language
level unit, we need to be conservative about possible entry points
there. */
- if ((TREE_PUBLIC (decl) && !DECL_COMDAT (decl) && !DECL_EXTERNAL (decl)))
+ if ((TREE_PUBLIC (decl) && !DECL_COMDAT (decl) && !DECL_EXTERNAL (decl))
+ || DECL_STATIC_CONSTRUCTOR (decl)
+ || DECL_STATIC_DESTRUCTOR (decl))
cgraph_mark_reachable_node (node);
/* If we've not yet emitted decl, tell the debug info about it. */
@@ -1219,8 +1216,7 @@ cgraph_mark_functions_to_output (void)
outside the current compilation unit. */
if (node->analyzed
&& !node->global.inlined_to
- && (node->needed || node->reachable_from_other_partition
- || node->address_taken
+ && (!cgraph_only_called_directly_p (node)
|| (e && node->reachable))
&& !TREE_ASM_WRITTEN (decl)
&& !DECL_EXTERNAL (decl))
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 878b6aa242e3..423729ba81aa 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2010-08-20 Jan Hubicka <jh@suse.cz>
+
+ PR c++/45307
+ PR c++/17736
+ * gcc.dg/ipa/ctor-empty-1.c: Add testcase.
+ * g++.dg/tree-ssa/empty-2.C: Check that constructor got optimized out.
+
2010-08-20 H.J. Lu <hongjiu.lu@intel.com>
PR target/45336
diff --git a/gcc/testsuite/g++.dg/tree-ssa/empty-2.C b/gcc/testsuite/g++.dg/tree-ssa/empty-2.C
index 728678af30e1..2036bebe3046 100644
--- a/gcc/testsuite/g++.dg/tree-ssa/empty-2.C
+++ b/gcc/testsuite/g++.dg/tree-ssa/empty-2.C
@@ -1,8 +1,11 @@
// PR c++/45307
-// { dg-options -fdump-tree-gimple }
+// { dg-options "-fdump-tree-gimple -fdump-tree-optimized" }
struct fallible_t { };
const fallible_t fallible = fallible_t();
// { dg-final { scan-tree-dump-not "fallible" "gimple" } }
+// Whole constructor should be optimized away.
+// { dg-final { scan-tree-dump-not "int" "optimized" } }
// { dg-final { cleanup-tree-dump "gimple" } }
+// { dg-final { cleanup-tree-dump "optimized" } }
diff --git a/gcc/testsuite/gcc.dg/ipa/ctor-empty-1.c b/gcc/testsuite/gcc.dg/ipa/ctor-empty-1.c
new file mode 100644
index 000000000000..9cd2b09fb0da
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/ipa/ctor-empty-1.c
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -c -fdump-ipa-whole-program" } */
+static __attribute__((constructor))
+void empty_constructor()
+{
+}
+/* { dg-final { scan-ipa-dump "Reclaiming functions: empty_constructor" "whole-program" } } */
+/* { dg-final { cleanup-ipa-dump "whole-program" } } */
--
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