[PATCH] Recognize clones for all contexts in SCCs in IPA-CP

[Martin Jambor <mjambor at suse dot cz>]

Hi,

in IPA-CP, a few functions look at callees of cgraph edges to see if
they still lead to the original node (those still need to be examined
or re-examined) or to a clone (those are considered already decided
and should be left alone).  The problem is that currently, when
looking at an SCC, these functions decide not to "close" the SCC by
switching the last edge from a specialized clone to a specialized
clone because it already leads to a clone, albeit one for all
contexts.

In the testcase ipcp-agg-7.c that is part of this patch, this leads to
two copies of foo, one of them not specialized for known aggregate
values, even though there should have been just one.

The patch fixes this by introducing another flag is_all_contexts_clone
and testing it in the necessary functions.  In order to avoid
confusion, I renamed already existing flag clone_for_all_contexts to
do_clone_for_all_contexts.

Additionally, I discovered that decide_whether_version_node contains a
bogus "|| !plats->aggs" in a test, which is harmless but just should
not be there, so I removed it.

Bootstrapped and tested on x86_64-linux.  OK for trunk?

Martin


2012-11-20  Martin Jambor  <mjambor@suse.cz>

	* ipa-prop.h (struct ipa_node_params): Rename clone_for_all_contexts to
	do_clone_for_all_contexts.  Update all uses.  New flag
	is_all_contexts_clone.

	* ipa-cp.c (cgraph_edge_brings_value_p): Also consider the case when cs
	leads to the clone for all contexts.
	(perhaps_add_new_callers): Likewise.
	(decide_whether_version_node): Remove bogus !plats->aggs test.  Set
	is_all_contexts_clone when cloning for all contexts.

	* testsuite/gcc.dg/ipa/ipcp-agg-7.c: New test.
	* testsuite/gcc.dg/ipa/ipcp-agg-8.c: Likewise.

Index: src/gcc/ipa-cp.c
===================================================================
--- src.orig/gcc/ipa-cp.c
+++ src/gcc/ipa-cp.c
@@ -1828,7 +1828,7 @@ estimate_local_effects (struct cgraph_no
       if (size <= 0
 	  || cgraph_will_be_removed_from_program_if_no_direct_calls (node))
 	{
-	  info->clone_for_all_contexts = true;
+	  info->do_clone_for_all_contexts = true;
 	  base_time = time;
 
 	  if (dump_file)
@@ -1841,7 +1841,7 @@ estimate_local_effects (struct cgraph_no
 	{
 	  if (size + overall_size <= max_new_size)
 	    {
-	      info->clone_for_all_contexts = true;
+	      info->do_clone_for_all_contexts = true;
 	      base_time = time;
 	      overall_size += size;
 
@@ -2314,8 +2314,9 @@ cgraph_edge_brings_value_p (struct cgrap
 			    struct ipcp_value_source *src)
 {
   struct ipa_node_params *caller_info = IPA_NODE_REF (cs->caller);
+  struct ipa_node_params *dst_info = IPA_NODE_REF (cs->callee);
 
-  if (IPA_NODE_REF (cs->callee)->ipcp_orig_node
+  if ((dst_info->ipcp_orig_node && !dst_info->is_all_contexts_clone)
       || caller_info->node_dead)
     return false;
   if (!src->val)
@@ -3177,8 +3178,9 @@ perhaps_add_new_callers (struct cgraph_n
       while (cs)
 	{
 	  enum availability availability;
-
-	  if (cgraph_function_node (cs->callee, &availability) == node
+	  struct cgraph_node *dst = cgraph_function_node (cs->callee,
+							  &availability);
+	  if ((dst == node || IPA_NODE_REF (dst)->is_all_contexts_clone)
 	      && availability > AVAIL_OVERWRITABLE
 	      && cgraph_edge_brings_value_p (cs, src))
 	    {
@@ -3337,8 +3339,8 @@ decide_whether_version_node (struct cgra
 	     cgraph_node_name (node), node->uid);
 
   gather_context_independent_values (info, &known_csts, &known_binfos,
-				     info->clone_for_all_contexts ? &known_aggs
-				     : NULL, NULL);
+				  info->do_clone_for_all_contexts ? &known_aggs
+				  : NULL, NULL);
 
   for (i = 0; i < count ;i++)
     {
@@ -3353,7 +3355,7 @@ decide_whether_version_node (struct cgra
 	  ret |= decide_about_value (node, i, -1, val, known_csts,
 				     known_binfos);
 
-      if (!plats->aggs_bottom || !plats->aggs)
+      if (!plats->aggs_bottom)
 	{
 	  struct ipcp_agg_lattice *aglat;
 	  struct ipcp_value *val;
@@ -3370,8 +3372,9 @@ decide_whether_version_node (struct cgra
         info = IPA_NODE_REF (node);
     }
 
-  if (info->clone_for_all_contexts)
+  if (info->do_clone_for_all_contexts)
     {
+      struct cgraph_node *clone;
       vec<cgraph_edge_p> callers;
 
       if (dump_file)
@@ -3381,11 +3384,12 @@ decide_whether_version_node (struct cgra
 
       callers = collect_callers_of_node (node);
       move_binfos_to_values (known_csts, known_binfos);
-      create_specialized_node (node, known_csts,
+      clone = create_specialized_node (node, known_csts,
 			       known_aggs_to_agg_replacement_list (known_aggs),
 			       callers);
       info = IPA_NODE_REF (node);
-      info->clone_for_all_contexts = false;
+      info->do_clone_for_all_contexts = false;
+      IPA_NODE_REF (clone)->is_all_contexts_clone = true;
       ret = true;
     }
   else
Index: src/gcc/ipa-prop.h
===================================================================
--- src.orig/gcc/ipa-prop.h
+++ src/gcc/ipa-prop.h
@@ -328,7 +328,9 @@ struct ipa_node_params
   unsigned node_enqueued : 1;
   /* Whether we should create a specialized version based on values that are
      known to be constant in all contexts.  */
-  unsigned clone_for_all_contexts : 1;
+  unsigned do_clone_for_all_contexts : 1;
+  /* Set if this is an IPA-CP clone for all contexts.  */
+  unsigned is_all_contexts_clone : 1;
   /* Node has been completely replaced by clones and will be removed after
      ipa-cp is finished.  */
   unsigned node_dead : 1;
Index: src/gcc/testsuite/gcc.dg/ipa/ipcp-agg-7.c
===================================================================
--- /dev/null
+++ src/gcc/testsuite/gcc.dg/ipa/ipcp-agg-7.c
@@ -0,0 +1,54 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -fno-ipa-sra -fdump-ipa-cp-details -fdump-tree-optimized-slim"  } */
+/* { dg-add-options bind_pic_locally } */
+
+struct S
+{
+  int a, b, c;
+};
+
+void *blah(int, void *);
+
+static void __attribute__ ((noinline)) foo (int x, int z, struct S *p);
+
+static void __attribute__ ((noinline))
+bar (int x, int z, struct S *p)
+{
+  foo (z, x, p);
+}
+
+static void __attribute__ ((noinline))
+foo (int x, int z, struct S *p)
+{
+  int i, c = p->c;
+  int b = p->b - z;
+  void *v = (void *) p;
+
+  if (z)
+    {
+      z--;
+      bar (z, x, p);
+    }
+  for (i = 0; i< c; i++)
+    v = blah(b + x + i, v);
+}
+
+void
+entry (int c)
+{
+  struct S s;
+  int i;
+
+  for (i = 0; i<c; i++)
+    {
+      s.a = c;
+      s.b = 64;
+      s.c = 32;
+      foo (4, i, &s);
+    }
+}
+/* { dg-final { scan-ipa-dump-times "Clone of bar" 1 "cp" } } */
+/* { dg-final { scan-ipa-dump-times "Clone of foo" 1 "cp" } } */
+/* { dg-final { cleanup-ipa-dump "cp" } } */
+/* { dg-final { scan-tree-dump-not "->c;" "optimized" } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */
Index: src/gcc/testsuite/gcc.dg/ipa/ipcp-agg-8.c
===================================================================
--- /dev/null
+++ src/gcc/testsuite/gcc.dg/ipa/ipcp-agg-8.c
@@ -0,0 +1,52 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -fno-ipa-sra -fdump-tree-optimized-slim"  } */
+/* { dg-add-options bind_pic_locally } */
+
+struct S
+{
+  int a, b, c;
+};
+
+void *blah(int, void *);
+
+static void __attribute__ ((noinline)) foo (int x, int z, struct S *p);
+
+static void __attribute__ ((noinline))
+bar (int x, int z, struct S *p)
+{
+  p->b = 0;
+  foo (z, x, p);
+}
+
+static void __attribute__ ((noinline))
+foo (int x, int z, struct S *p)
+{
+  int i, c = p->c;
+  int b = p->b - z;
+  void *v = (void *) p;
+
+  if (z)
+    {
+      z--;
+      bar (z, x, p);
+    }
+  for (i = 0; i< c; i++)
+    v = blah(b + x + i, v);
+}
+
+void
+entry (int c)
+{
+  struct S s;
+  int i;
+
+  for (i = 0; i<c; i++)
+    {
+      s.a = c;
+      s.b = 64;
+      s.c = 32;
+      foo (4, i, &s);
+    }
+}
+/* { dg-final { scan-tree-dump "->b;" "optimized" } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */