ipa-prop.h: Include alloc-pool.h, all sorts of updates to general comments.

2011-07-18  Martin Jambor  <mjambor@suse.cz>

	* ipa-prop.h: Include alloc-pool.h, all sorts of updates to general
	comments.
	(ipcp_values_pool): Declare.
	(ipcp_sources_pool): Likewise.
	(ipcp_lattice): Changed to forward declaration.
	(ipa_param_descriptor): Removed fields ipcp_lattice, types and
	cannot_devirtualize.
	(ipa_node_params): New fields descriptors, lattices, known_vals,
	clone_for_all_contexts and node dead, removed fields params and
	count_scale.
	(ipa_set_param_count): Removed.
	(ipa_get_param_count): Made to work with descriptors vector.
	(ipa_get_param): Updated.
	(ipa_param_cannot_devirtualize_p): Removed.
	(ipa_param_types_vec_empty): Likewise.
	(ipa_set_param_used): New function.
	(ipa_get_param_used): Updated to use descriptors vector.
	(ipa_func_list): Removed.
	(ipa_init_func_list): Removed declaration.
	(ipa_push_func_to_list_1): Likewise.
	(ipa_pop_func_from_list): Likewise.
	(ipa_push_func_to_list): Removed.
	(ipa_lattice_from_jfunc): Remove declaration.
	(ipa_get_jf_pass_through_result): Declare.
	(ipa_get_jf_ancestor_result): Likewise.
	(ipa_value_from_jfunc): Likewise.
	(ipa_get_lattice): Update.
	(ipa_lat_is_single_const): New function.
	* ipa-prop.c (ipa_push_func_to_list_1): Removed.
	(ipa_init_func_list): Likewise.
	(ipa_pop_func_from_list): Likewise.
	(ipa_get_param_decl_index): Fix coding style.
	(count_formal_params): Removed.
	(count_formal_params_1): Renamed to count_formal_params.
	(ipa_populate_param_decls): Update to use descriptors vector.
	(ipa_initialize_node_params): Likewise.
	(visit_ref_for_mod_analysis): Use ipa_set_param_used.
	(ipa_analyze_params_uses): Likewise.
	(ipa_free_node_params_substructures): Likewise and free also lattices
	and known values.
	(duplicate_array): Removed.
	(ipa_edge_duplication_hook): Add the new edge to the list of edge
	clones.
	(ipa_node_duplication_hook): Update to use new lattices.
	(ipa_free_all_structures_after_ipa_cp): Free alloc pools.
	(ipa_free_all_structures_after_iinln): Likewise.
	(ipa_write_node_info): Update to use new lattices.
	(ipa_read_node_info): Likewise.
	(ipa_get_jf_pass_through_result): New function.
	(ipa_get_jf_ancestor_result): Likewise.
	(ipa_value_from_jfunc): Likewise.
	(ipa_cst_from_jfunc): Reimplemented using ipa_value_from_jfunc.
	* ipa-cp.c: Reimplemented.
	* params.def (PARAM_DEVIRT_TYPE_LIST_SIZE): Removed.
	(PARAM_IPA_CP_VALUE_LIST_SIZE): New parameter.
	(PARAM_IPA_CP_EVAL_THRESHOLD): Likewise.
	* Makefile.in (IPA_PROP_H): Added alloc-pool.h to dependencies.

	* doc/invoke.texi (devirt-type-list-size): Removed description.
	(ipa-cp-value-list-size): Added description.

	* testsuite/gcc.dg/ipa/ipa-1.c: Updated testcase dump scan.
	* testsuite/gcc.dg/ipa/ipa-2.c: Likewise.
	* testsuite/gcc.dg/ipa/ipa-3.c: Likewise and made functions static.
	* testsuite/gcc.dg/ipa/ipa-4.c: Updated testcase dump scan.
	* testsuite/gcc.dg/ipa/ipa-5.c: Likewise.
	* testsuite/gcc.dg/ipa/ipa-7.c: Likewise.
	* testsuite/gcc.dg/ipa/ipa-8.c: Updated testcase dump scan.
	* testsuite/gcc.dg/ipa/ipacost-1.c: Likewise.
	* testsuite/gcc.dg/ipa/ipacost-2.c: Likewise and increased sizes
	of some functions.
	* testsuite/gcc.dg/ipa/ipcp-1.c: New test.
	* testsuite/gcc.dg/ipa/ipcp-2.c: Likewise.
	* testsuite/gcc.dg/tree-ssa/ipa-cp-1.c: Updated testcase.

From-SVN: r176424

gcc/ChangeLog

+2011-07-18  Martin Jambor  <mjambor@suse.cz>
+
+	* ipa-prop.h: Include alloc-pool.h, all sorts of updates to general
+	comments.
+	(ipcp_values_pool): Declare.
+	(ipcp_sources_pool): Likewise.
+	(ipcp_lattice): Changed to forward declaration.
+	(ipa_param_descriptor): Removed fields ipcp_lattice, types and
+	cannot_devirtualize.
+	(ipa_node_params): New fields descriptors, lattices, known_vals,
+	clone_for_all_contexts and node dead, removed fields params and
+	count_scale.
+	(ipa_set_param_count): Removed.
+	(ipa_get_param_count): Made to work with descriptors vector.
+	(ipa_get_param): Updated.
+	(ipa_param_cannot_devirtualize_p): Removed.
+	(ipa_param_types_vec_empty): Likewise.
+	(ipa_set_param_used): New function.
+	(ipa_get_param_used): Updated to use descriptors vector.
+	(ipa_func_list): Removed.
+	(ipa_init_func_list): Removed declaration.
+	(ipa_push_func_to_list_1): Likewise.
+	(ipa_pop_func_from_list): Likewise.
+	(ipa_push_func_to_list): Removed.
+	(ipa_lattice_from_jfunc): Remove declaration.
+	(ipa_get_jf_pass_through_result): Declare.
+	(ipa_get_jf_ancestor_result): Likewise.
+	(ipa_value_from_jfunc): Likewise.
+	(ipa_get_lattice): Update.
+	(ipa_lat_is_single_const): New function.
+	* ipa-prop.c (ipa_push_func_to_list_1): Removed.
+	(ipa_init_func_list): Likewise.
+	(ipa_pop_func_from_list): Likewise.
+	(ipa_get_param_decl_index): Fix coding style.
+	(count_formal_params): Removed.
+	(count_formal_params_1): Renamed to count_formal_params.
+	(ipa_populate_param_decls): Update to use descriptors vector.
+	(ipa_initialize_node_params): Likewise.
+	(visit_ref_for_mod_analysis): Use ipa_set_param_used.
+	(ipa_analyze_params_uses): Likewise.
+	(ipa_free_node_params_substructures): Likewise and free also lattices
+	and known values.
+	(duplicate_array): Removed.
+	(ipa_edge_duplication_hook): Add the new edge to the list of edge
+	clones.
+	(ipa_node_duplication_hook): Update to use new lattices.
+	(ipa_free_all_structures_after_ipa_cp): Free alloc pools.
+	(ipa_free_all_structures_after_iinln): Likewise.
+	(ipa_write_node_info): Update to use new lattices.
+	(ipa_read_node_info): Likewise.
+	(ipa_get_jf_pass_through_result): New function.
+	(ipa_get_jf_ancestor_result): Likewise.
+	(ipa_value_from_jfunc): Likewise.
+	(ipa_cst_from_jfunc): Reimplemented using ipa_value_from_jfunc.
+	* ipa-cp.c: Reimplemented.
+	* params.def (PARAM_DEVIRT_TYPE_LIST_SIZE): Removed.
+	(PARAM_IPA_CP_VALUE_LIST_SIZE): New parameter.
+	(PARAM_IPA_CP_EVAL_THRESHOLD): Likewise.
+	* Makefile.in (IPA_PROP_H): Added alloc-pool.h to dependencies.
+	* doc/invoke.texi (devirt-type-list-size): Removed description.
+	(ipa-cp-value-list-size): Added description.
+
 2011-07-18  Richard Henderson  <rth@redhat.com>
 
 	* bb-reorder.c (fix_crossing_conditional_branches): Emit all insns

gcc/Makefile.in

@@ -1006,7 +1006,7 @@ LTO_STREAMER_H = lto-streamer.h $(LINKER_PLUGIN_API_H) $(TARGET_H) \
 		$(CGRAPH_H) $(VEC_H) vecprim.h $(TREE_H) $(GIMPLE_H) \
 		$(GCOV_IO_H)
 TREE_VECTORIZER_H = tree-vectorizer.h $(TREE_DATA_REF_H)
-IPA_PROP_H = ipa-prop.h $(TREE_H) $(VEC_H) $(CGRAPH_H) $(GIMPLE_H)
+IPA_PROP_H = ipa-prop.h $(TREE_H) $(VEC_H) $(CGRAPH_H) $(GIMPLE_H) alloc-pool.h
 GSTAB_H = gstab.h stab.def
 BITMAP_H = bitmap.h $(HASHTAB_H) statistics.h
 GCC_PLUGIN_H = gcc-plugin.h highlev-plugin-common.h $(CONFIG_H) $(SYSTEM_H) \

gcc/doc/invoke.texi

@@ -9006,11 +9006,11 @@ loop in the loop nest by a given number of iterations.  The strip
 length can be changed using the @option{loop-block-tile-size}
 parameter.  The default value is 51 iterations.
 
-@item devirt-type-list-size
-IPA-CP attempts to track all possible types passed to a function's
-parameter in order to perform devirtualization.
-@option{devirt-type-list-size} is the maximum number of types it
-stores per a single formal parameter of a function.
+@item ipa-cp-value-list-size
+IPA-CP attempts to track all possible values and types passed to a function's
+parameter in order to propagate them and perform devirtualization.
+@option{ipa-cp-value-list-size} is the maximum number of values and types it
+stores per one formal parameter of a function.
 
 @item lto-partitions
 Specify desired number of partitions produced during WHOPR compilation.

gcc/ipa-prop.c

@@ -65,65 +65,6 @@ static struct cgraph_2edge_hook_list *edge_duplication_hook_holder;
 static struct cgraph_2node_hook_list *node_duplication_hook_holder;
 static struct cgraph_node_hook_list *function_insertion_hook_holder;
 
-/* Add cgraph NODE described by INFO to the worklist WL regardless of whether
-   it is in one or not.  It should almost never be used directly, as opposed to
-   ipa_push_func_to_list.  */
-
-void
-ipa_push_func_to_list_1 (struct ipa_func_list **wl,
-			 struct cgraph_node *node,
-			 struct ipa_node_params *info)
-{
-  struct ipa_func_list *temp;
-
-  info->node_enqueued = 1;
-  temp = XCNEW (struct ipa_func_list);
-  temp->node = node;
-  temp->next = *wl;
-  *wl = temp;
-}
-
-/* Initialize worklist to contain all functions.  */
-
-struct ipa_func_list *
-ipa_init_func_list (void)
-{
-  struct cgraph_node *node;
-  struct ipa_func_list * wl;
-
-  wl = NULL;
-  for (node = cgraph_nodes; node; node = node->next)
-    if (node->analyzed && !node->alias)
-      {
-	struct ipa_node_params *info = IPA_NODE_REF (node);
-	/* Unreachable nodes should have been eliminated before ipcp and
-	   inlining.  */
-	gcc_assert (node->needed || node->reachable);
-	ipa_push_func_to_list_1 (&wl, node, info);
-      }
-
-  return wl;
-}
-
-/* Remove a function from the worklist WL and return it.  */
-
-struct cgraph_node *
-ipa_pop_func_from_list (struct ipa_func_list **wl)
-{
-  struct ipa_node_params *info;
-  struct ipa_func_list *first;
-  struct cgraph_node *node;
-
-  first = *wl;
-  *wl = (*wl)->next;
-  node = first->node;
-  free (first);
-
-  info = IPA_NODE_REF (node);
-  info->node_enqueued = 0;
-  return node;
-}
-
 /* Return index of the formal whose tree is PTREE in function which corresponds
    to INFO.  */
 
@@ -134,7 +75,7 @@ ipa_get_param_decl_index (struct ipa_node_params *info, tree ptree)
 
   count = ipa_get_param_count (info);
   for (i = 0; i < count; i++)
-    if (ipa_get_param(info, i) == ptree)
+    if (ipa_get_param (info, i) == ptree)
       return i;
 
   return -1;
@@ -157,7 +98,8 @@ ipa_populate_param_decls (struct cgraph_node *node,
   param_num = 0;
   for (parm = fnargs; parm; parm = DECL_CHAIN (parm))
     {
-      info->params[param_num].decl = parm;
+      VEC_index (ipa_param_descriptor_t,
+		 info->descriptors, param_num)->decl = parm;
       param_num++;
     }
 }
@@ -165,7 +107,7 @@ ipa_populate_param_decls (struct cgraph_node *node,
 /* Return how many formal parameters FNDECL has.  */
 
 static inline int
-count_formal_params_1 (tree fndecl)
+count_formal_params (tree fndecl)
 {
   tree parm;
   int count = 0;
@@ -176,19 +118,6 @@ count_formal_params_1 (tree fndecl)
   return count;
 }
 
-/* Count number of formal parameters in NOTE. Store the result to the
-   appropriate field of INFO.  */
-
-static void
-ipa_count_formal_params (struct cgraph_node *node,
-			 struct ipa_node_params *info)
-{
-  int param_num;
-
-  param_num = count_formal_params_1 (node->decl);
-  ipa_set_param_count (info, param_num);
-}
-
 /* Initialize the ipa_node_params structure associated with NODE by counting
    the function parameters, creating the descriptors and populating their
    param_decls.  */
@@ -198,12 +127,17 @@ ipa_initialize_node_params (struct cgraph_node *node)
 {
   struct ipa_node_params *info = IPA_NODE_REF (node);
 
-  if (!info->params)
+  if (!info->descriptors)
     {
-      ipa_count_formal_params (node, info);
-      info->params = XCNEWVEC (struct ipa_param_descriptor,
-				    ipa_get_param_count (info));
-      ipa_populate_param_decls (node, info);
+      int param_count;
+
+      param_count = count_formal_params (node->decl);
+      if (param_count)
+	{
+	  VEC_safe_grow_cleared (ipa_param_descriptor_t, heap,
+				 info->descriptors, param_count);
+	  ipa_populate_param_decls (node, info);
+	}
     }
 }
 
@@ -1497,7 +1431,7 @@ visit_ref_for_mod_analysis (gimple stmt ATTRIBUTE_UNUSED,
     {
       int index = ipa_get_param_decl_index (info, op);
       gcc_assert (index >= 0);
-      info->params[index].used = true;
+      ipa_set_param_used (info, index, true);
     }
 
   return false;
@@ -1529,7 +1463,7 @@ ipa_analyze_params_uses (struct cgraph_node *node,
 	 the flag during modification analysis.  */
       if (is_gimple_reg (parm)
 	  && gimple_default_def (DECL_STRUCT_FUNCTION (node->decl), parm))
-	info->params[i].used = true;
+	ipa_set_param_used (info, i, true);
     }
 
   func = DECL_STRUCT_FUNCTION (decl);
@@ -1936,8 +1870,11 @@ ipa_free_all_edge_args (void)
 void
 ipa_free_node_params_substructures (struct ipa_node_params *info)
 {
-  free (info->params);
-
+  VEC_free (ipa_param_descriptor_t, heap, info->descriptors);
+  free (info->lattices);
+  /* Lattice values and their sources are deallocated with their alocation
+     pool.  */
+  VEC_free (tree, heap, info->known_vals);
   memset (info, 0, sizeof (*info));
 }
 
@@ -1980,22 +1917,6 @@ ipa_node_removal_hook (struct cgraph_node *node, void *data ATTRIBUTE_UNUSED)
   ipa_free_node_params_substructures (IPA_NODE_REF (node));
 }
 
-/* Helper function to duplicate an array of size N that is at SRC and store a
-   pointer to it to DST.  Nothing is done if SRC is NULL.  */
-
-static void *
-duplicate_array (void *src, size_t n)
-{
-  void *p;
-
-  if (!src)
-    return NULL;
-
-  p = xmalloc (n);
-  memcpy (p, src, n);
-  return p;
-}
-
 static struct ipa_jump_func *
 duplicate_ipa_jump_func_array (const struct ipa_jump_func * src, size_t n)
 {
@@ -2040,22 +1961,15 @@ ipa_node_duplication_hook (struct cgraph_node *src, struct cgraph_node *dst,
 			   ATTRIBUTE_UNUSED void *data)
 {
   struct ipa_node_params *old_info, *new_info;
-  int param_count, i;
 
   ipa_check_create_node_params ();
   old_info = IPA_NODE_REF (src);
   new_info = IPA_NODE_REF (dst);
-  param_count = ipa_get_param_count (old_info);
 
-  ipa_set_param_count (new_info, param_count);
-  new_info->params = (struct ipa_param_descriptor *)
-    duplicate_array (old_info->params,
-		     sizeof (struct ipa_param_descriptor) * param_count);
-  for (i = 0; i < param_count; i++)
-    new_info->params[i].types = VEC_copy (tree, heap,
- 					  old_info->params[i].types);
+  new_info->descriptors = VEC_copy (ipa_param_descriptor_t, heap,
+				    old_info->descriptors);
+  new_info->lattices = NULL;
   new_info->ipcp_orig_node = old_info->ipcp_orig_node;
-  new_info->count_scale = old_info->count_scale;
 
   new_info->called_with_var_arguments = old_info->called_with_var_arguments;
   new_info->uses_analysis_done = old_info->uses_analysis_done;
@@ -2127,6 +2041,8 @@ ipa_free_all_structures_after_ipa_cp (void)
     {
       ipa_free_all_edge_args ();
       ipa_free_all_node_params ();
+      free_alloc_pool (ipcp_sources_pool);
+      free_alloc_pool (ipcp_values_pool);
       ipa_unregister_cgraph_hooks ();
     }
 }
@@ -2142,6 +2058,10 @@ ipa_free_all_structures_after_iinln (void)
   ipa_free_all_edge_args ();
   ipa_free_all_node_params ();
   ipa_unregister_cgraph_hooks ();
+  if (ipcp_sources_pool)
+    free_alloc_pool (ipcp_sources_pool);
+  if (ipcp_values_pool)
+    free_alloc_pool (ipcp_values_pool);
 }
 
 /* Print ipa_tree_map data structures of all functions in the
@@ -2196,7 +2116,7 @@ ipa_get_vector_of_formal_parms (tree fndecl)
   int count;
   tree parm;
 
-  count = count_formal_params_1 (fndecl);
+  count = count_formal_params (fndecl);
   args = VEC_alloc (tree, heap, count);
   for (parm = DECL_ARGUMENTS (fndecl); parm; parm = DECL_CHAIN (parm))
     VEC_quick_push (tree, args, parm);
@@ -2859,7 +2779,7 @@ ipa_write_node_info (struct output_block *ob, struct cgraph_node *node)
   gcc_assert (!info->node_enqueued);
   gcc_assert (!info->ipcp_orig_node);
   for (j = 0; j < ipa_get_param_count (info); j++)
-    bp_pack_value (&bp, info->params[j].used, 1);
+    bp_pack_value (&bp, ipa_is_param_used (info, j), 1);
   lto_output_bitpack (&bp);
   for (e = node->callees; e; e = e->next_callee)
     {
@@ -2900,7 +2820,7 @@ ipa_read_node_info (struct lto_input_block *ib, struct cgraph_node *node,
     info->uses_analysis_done = true;
   info->node_enqueued = false;
   for (k = 0; k < ipa_get_param_count (info); k++)
-    info->params[k].used = bp_unpack_value (&bp, 1);
+    ipa_set_param_used (info, k, bp_unpack_value (&bp, 1));
   for (e = node->callees; e; e = e->next_callee)
     {
       struct ipa_edge_args *args = IPA_EDGE_REF (e);
@@ -3064,82 +2984,3 @@ ipa_update_after_lto_read (void)
 	}
 }
 
-/* Given the jump function JFUNC, compute the lattice LAT that describes the
-   value coming down the callsite. INFO describes the caller node so that
-   pass-through jump functions can be evaluated.  */
-
-void
-ipa_lattice_from_jfunc (struct ipa_node_params *info, struct ipcp_lattice *lat,
-			 struct ipa_jump_func *jfunc)
-{
-  if (jfunc->type == IPA_JF_CONST)
-    {
-      lat->type = IPA_CONST_VALUE;
-      lat->constant = jfunc->value.constant;
-    }
-  else if (jfunc->type == IPA_JF_PASS_THROUGH)
-    {
-      struct ipcp_lattice *caller_lat;
-      tree cst;
-
-      caller_lat = ipa_get_lattice (info, jfunc->value.pass_through.formal_id);
-      lat->type = caller_lat->type;
-      if (caller_lat->type != IPA_CONST_VALUE)
-	return;
-      cst = caller_lat->constant;
-
-      if (jfunc->value.pass_through.operation != NOP_EXPR)
-	{
-	  tree restype;
-	  if (TREE_CODE_CLASS (jfunc->value.pass_through.operation)
-	      == tcc_comparison)
-	    restype = boolean_type_node;
-	  else
-	    restype = TREE_TYPE (cst);
-	  cst = fold_binary (jfunc->value.pass_through.operation,
-			     restype, cst, jfunc->value.pass_through.operand);
-	}
-      if (!cst || !is_gimple_ip_invariant (cst))
-	lat->type = IPA_BOTTOM;
-      lat->constant = cst;
-    }
-  else if (jfunc->type == IPA_JF_ANCESTOR)
-    {
-      struct ipcp_lattice *caller_lat;
-      tree t;
-
-      caller_lat = ipa_get_lattice (info, jfunc->value.ancestor.formal_id);
-      lat->type = caller_lat->type;
-      if (caller_lat->type != IPA_CONST_VALUE)
-	return;
-      if (TREE_CODE (caller_lat->constant) != ADDR_EXPR)
-	{
-	  /* This can happen when the constant is a NULL pointer.  */
-	  lat->type = IPA_BOTTOM;
-	  return;
-	}
-      t = TREE_OPERAND (caller_lat->constant, 0);
-      t = build_ref_for_offset (EXPR_LOCATION (t), t,
-				jfunc->value.ancestor.offset,
-				jfunc->value.ancestor.type, NULL, false);
-      lat->constant = build_fold_addr_expr (t);
-    }
-  else
-    lat->type = IPA_BOTTOM;
-}
-
-/* Determine whether JFUNC evaluates to a constant and if so, return it.
-   Otherwise return NULL. INFO describes the caller node so that pass-through
-   jump functions can be evaluated.  */
-
-tree
-ipa_cst_from_jfunc (struct ipa_node_params *info, struct ipa_jump_func *jfunc)
-{
-  struct ipcp_lattice lat;
-
-  ipa_lattice_from_jfunc (info, &lat, jfunc);
-  if (lat.type == IPA_CONST_VALUE)
-    return lat.constant;
-  else
-    return NULL_TREE;
-}

gcc/ipa-prop.h

@@ -25,6 +25,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "vec.h"
 #include "cgraph.h"
 #include "gimple.h"
+#include "alloc-pool.h"
 
 /* The following definitions and interfaces are used by
    interprocedural analyses or parameters.  */
@@ -32,7 +33,10 @@ along with GCC; see the file COPYING3.  If not see
 /* ipa-prop.c stuff (ipa-cp, indirect inlining):  */
 
 /* A jump function for a callsite represents the values passed as actual
-   arguments of the callsite. There are three main types of values :
+   arguments of the callsite.  They were originally proposed in a paper called
+   "Interprocedural Constant Propagation", by David Callahan, Keith D Cooper,
+   Ken Kennedy, Linda Torczon in Comp86, pg 152-161.  There are three main
+   types of values :
 
    Pass-through - the caller's formal parameter is passed as an actual
                   argument, possibly one simple operation performed on it.
@@ -41,7 +45,8 @@ along with GCC; see the file COPYING3.  If not see
    Unknown      - neither of the above.
 
    IPA_JF_CONST_MEMBER_PTR stands for C++ member pointers, it is a special
-   constant in this regard.  Other constants are represented with IPA_JF_CONST.
+   constant in this regard because it is in fact a structure consisting of two
+   values.  Other constants are represented with IPA_JF_CONST.
 
    IPA_JF_ANCESTOR is a special pass-through jump function, which means that
    the result is an address of a part of the object pointed to by the formal
@@ -130,95 +135,65 @@ struct GTY (()) ipa_jump_func
   } GTY ((desc ("%1.type"))) value;
 };
 
-/* All formal parameters in the program have a lattice associated with it
-   computed by the interprocedural stage of IPCP.
-   There are three main values of the lattice:
-   IPA_TOP - unknown,
-   IPA_BOTTOM - variable,
-   IPA_CONST_VALUE - simple scalar constant,
-
-   We also use this type to propagate types accross the call graph for the
-   purpose of devirtualization.  In that case, IPA_CONST_VALUE denotes a known
-   type, rather than a constant.  */
-enum ipa_lattice_type
-{
-  IPA_BOTTOM,
-  IPA_CONST_VALUE,
-  IPA_TOP
-};
+/* Summary describing a single formal parameter.  */
 
-/* All formal parameters in the program have a cval computed by
-   the interprocedural stage of IPCP. See enum ipa_lattice_type for
-   the various types of lattices supported */
-struct ipcp_lattice
-{
-  enum ipa_lattice_type type;
-  tree constant;
-};
-
-/* Structure describing a single formal parameter.  */
 struct ipa_param_descriptor
 {
-  /* IPA-CP lattice.  */
-  struct ipcp_lattice ipcp_lattice;
   /* PARAM_DECL of this parameter.  */
   tree decl;
-  /* Vector of BINFOs of types that this argument might encounter.  NULL
-     basically means a top value, bottom is marked by the cannot_devirtualize
-     flag below.*/
-  VEC (tree, heap) *types;
   /* The parameter is used.  */
   unsigned used : 1;
-  /* Set when parameter type cannot be used for devirtualization.  */
-  unsigned cannot_devirtualize : 1;
 };
 
+typedef struct ipa_param_descriptor ipa_param_descriptor_t;
+DEF_VEC_O (ipa_param_descriptor_t);
+DEF_VEC_ALLOC_O (ipa_param_descriptor_t, heap);
+struct ipcp_lattice;
+
 /* ipa_node_params stores information related to formal parameters of functions
    and some other information for interprocedural passes that operate on
    parameters (such as ipa-cp).  */
+
 struct ipa_node_params
 {
-  /* Number of formal parameters of this function.  When set to 0, this
-     function's parameters would not be analyzed by IPA CP.  */
-  int param_count;
+  /* Information about individual formal parameters that are gathered when
+     summaries are generated. */
+  VEC (ipa_param_descriptor_t, heap) *descriptors;
+  /* Pointer to an array of structures describing individual formal
+     parameters.  */
+  struct ipcp_lattice *lattices;
+  /* Only for versioned nodes this field would not be NULL,
+     it points to the node that IPA cp cloned from.  */
+  struct cgraph_node *ipcp_orig_node;
+  /* If this node is an ipa-cp clone, these are the known values that describe
+     what it has been specialized for.  */
+  VEC (tree, heap) *known_vals;
   /* Whether this function is called with variable number of actual
      arguments.  */
   unsigned called_with_var_arguments : 1;
+  /* Set when it is possible to create specialized versions of this node.  */
+  unsigned node_versionable : 1;
   /* Whether the param uses analysis has already been performed.  */
   unsigned uses_analysis_done : 1;
-  /* Whether the function is enqueued in an ipa_func_list.  */
+  /* Whether the function is enqueued in ipa-cp propagation stack.  */
   unsigned node_enqueued : 1;
-  /* Pointer to an array of structures describing individual formal
-     parameters.  */
-  struct ipa_param_descriptor *params;
-  /* Only for versioned nodes this field would not be NULL,
-     it points to the node that IPA cp cloned from.  */
-  struct cgraph_node *ipcp_orig_node;
-  /* Meaningful only for original functions.  Expresses the
-     ratio between the direct calls and sum of all invocations of
-     this function (given by profiling info).  It is used to calculate
-     the profiling information of the original function and the versioned
-     one.  */
-  gcov_type count_scale;
+  /* 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;
+  /* Node has been completely replaced by clones and will be removed after
+     ipa-cp is finished.  */
+  unsigned node_dead : 1;
 };
 
 /* ipa_node_params access functions.  Please use these to access fields that
    are or will be shared among various passes.  */
 
-/* Set the number of formal parameters. */
-
-static inline void
-ipa_set_param_count (struct ipa_node_params *info, int count)
-{
-  info->param_count = count;
-}
-
 /* Return the number of formal parameters. */
 
 static inline int
 ipa_get_param_count (struct ipa_node_params *info)
 {
-  return info->param_count;
+  return VEC_length (ipa_param_descriptor_t, info->descriptors);
 }
 
 /* Return the declaration of Ith formal parameter of the function corresponding
@@ -228,39 +203,25 @@ ipa_get_param_count (struct ipa_node_params *info)
 static inline tree
 ipa_get_param (struct ipa_node_params *info, int i)
 {
-  gcc_assert (i >= 0 && i <= info->param_count);
-  return info->params[i].decl;
-}
-
-/* Return the used flag corresponding to the Ith formal parameter of
-   the function associated with INFO.  */
-
-static inline bool
-ipa_is_param_used (struct ipa_node_params *info, int i)
-{
-  gcc_assert (i >= 0 && i <= info->param_count);
-  return info->params[i].used;
+  return VEC_index (ipa_param_descriptor_t, info->descriptors, i)->decl;
 }
 
-/* Return the cannot_devirtualize flag corresponding to the Ith formal
-   parameter of the function associated with INFO.  The corresponding function
-   to set the flag is ipa_set_param_cannot_devirtualize.  */
+/* Set the used flag corresponding to the Ith formal parameter of the function
+   associated with INFO to VAL.  */
 
-static inline bool
-ipa_param_cannot_devirtualize_p (struct ipa_node_params *info, int i)
+static inline void
+ipa_set_param_used (struct ipa_node_params *info, int i, bool val)
 {
-  gcc_assert (i >= 0 && i <= info->param_count);
-  return info->params[i].cannot_devirtualize;
+  VEC_index (ipa_param_descriptor_t, info->descriptors, i)->used = val;
 }
 
-/* Return true iff the vector of possible types of the Ith formal parameter of
-   the function associated with INFO is empty.  */
+/* Return the used flag corresponding to the Ith formal parameter of the
+   function associated with INFO.  */
 
 static inline bool
-ipa_param_types_vec_empty (struct ipa_node_params *info, int i)
+ipa_is_param_used (struct ipa_node_params *info, int i)
 {
-  gcc_assert (i >= 0 && i <= info->param_count);
-  return info->params[i].types == NULL;
+  return VEC_index (ipa_param_descriptor_t, info->descriptors, i)->used;
 }
 
 /* Flag this node as having callers with variable number of arguments.  */
@@ -279,8 +240,6 @@ ipa_is_called_with_var_arguments (struct ipa_node_params *info)
   return info->called_with_var_arguments;
 }
 
-
-
 /* ipa_edge_args stores information related to a callsite and particularly its
    arguments.  It can be accessed by the IPA_EDGE_REF macro.  */
 typedef struct GTY(()) ipa_edge_args
@@ -402,33 +361,6 @@ ipa_edge_args_info_available_for_edge_p (struct cgraph_edge *edge)
 					     ipa_edge_args_vector));
 }
 
-/* A function list element.  It is used to create a temporary worklist used in
-   the propagation stage of IPCP. (can be used for more IPA optimizations)  */
-struct ipa_func_list
-{
-  struct cgraph_node *node;
-  struct ipa_func_list *next;
-};
-
-/* ipa_func_list interface.  */
-struct ipa_func_list *ipa_init_func_list (void);
-void ipa_push_func_to_list_1 (struct ipa_func_list **, struct cgraph_node *,
-			      struct ipa_node_params *);
-struct cgraph_node *ipa_pop_func_from_list (struct ipa_func_list **);
-
-/* Add cgraph NODE to the worklist WL if it is not already in one.  */
-
-static inline void
-ipa_push_func_to_list (struct ipa_func_list **wl, struct cgraph_node *node)
-{
-  struct ipa_node_params *info = IPA_NODE_REF (node);
-
-  if (!info->node_enqueued)
-    ipa_push_func_to_list_1 (wl, node, info);
-}
-
-void ipa_analyze_node (struct cgraph_node *);
-
 /* Function formal parameters related computations.  */
 void ipa_initialize_node_params (struct cgraph_node *node);
 bool ipa_propagate_indirect_call_infos (struct cgraph_edge *cs,
@@ -438,12 +370,18 @@ bool ipa_propagate_indirect_call_infos (struct cgraph_edge *cs,
 struct cgraph_edge *ipa_make_edge_direct_to_target (struct cgraph_edge *, tree,
 						    tree);
 
+/* Functions related to both.  */
+void ipa_analyze_node (struct cgraph_node *);
 
 /* Debugging interface.  */
 void ipa_print_node_params (FILE *, struct cgraph_node *node);
 void ipa_print_all_params (FILE *);
 void ipa_print_node_jump_functions (FILE *f, struct cgraph_node *node);
 void ipa_print_all_jump_functions (FILE * f);
+void ipcp_verify_propagated_values (void);
+
+extern alloc_pool ipcp_values_pool;
+extern alloc_pool ipcp_sources_pool;
 
 /* Structure to describe transformations of formal parameters and actual
    arguments.  Each instance describes one new parameter and they are meant to
@@ -521,9 +459,6 @@ void ipa_prop_write_jump_functions (cgraph_node_set set);
 void ipa_prop_read_jump_functions (void);
 void ipa_update_after_lto_read (void);
 int ipa_get_param_decl_index (struct ipa_node_params *, tree);
-void ipa_lattice_from_jfunc (struct ipa_node_params *info,
-			     struct ipcp_lattice *lat,
-			     struct ipa_jump_func *jfunc);
 tree ipa_cst_from_jfunc (struct ipa_node_params *info,
 			 struct ipa_jump_func *jfunc);
 
@@ -532,13 +467,4 @@ tree ipa_cst_from_jfunc (struct ipa_node_params *info,
 tree build_ref_for_offset (location_t, tree, HOST_WIDE_INT, tree,
 			   gimple_stmt_iterator *, bool);
 
-/* Return the lattice corresponding to the Ith formal parameter of the function
-   described by INFO.  */
-static inline struct ipcp_lattice *
-ipa_get_lattice (struct ipa_node_params *info, int i)
-{
-  gcc_assert (i >= 0 && i <= info->param_count);
-  return &(info->params[i].ipcp_lattice);
-}
-
 #endif /* IPA_PROP_H */

gcc/params.def

@@ -860,12 +860,18 @@ DEFPARAM (PARAM_IPA_SRA_PTR_GROWTH_FACTOR,
 	  "a pointer to an aggregate with",
 	  2, 0, 0)
 
-DEFPARAM (PARAM_DEVIRT_TYPE_LIST_SIZE,
-	  "devirt-type-list-size",
-	  "Maximum size of a type list associated with each parameter for "
-	  "devirtualization",
+DEFPARAM (PARAM_IPA_CP_VALUE_LIST_SIZE,
+	  "ipa-cp-value-list-size",
+	  "Maximum size of a list of values associated with each parameter for "
+	  "interprocedural constant propagation",
 	  8, 0, 0)
 
+DEFPARAM (PARAM_IPA_CP_EVAL_THRESHOLD,
+	  "ipa-cp-eval-threshold",
+	  "Threshold ipa-cp opportunity evaluation that is still considered "
+	  "beneficial to clone.",
+	  500, 0, 0)
+
 /* WHOPR partitioning configuration.  */
 
 DEFPARAM (PARAM_LTO_PARTITIONS,

gcc/testsuite/ChangeLog

+2011-07-18  Martin Jambor  <mjambor@suse.cz>
+
+	* gcc.dg/ipa/ipa-1.c: Updated testcase dump scan.
+	* gcc.dg/ipa/ipa-2.c: Likewise.
+	* gcc.dg/ipa/ipa-3.c: Likewise and made functions static.
+	* gcc.dg/ipa/ipa-4.c: Updated testcase dump scan.
+	* gcc.dg/ipa/ipa-5.c: Likewise.
+	* gcc.dg/ipa/ipa-7.c: Likewise.
+	* gcc.dg/ipa/ipa-8.c: Updated testcase dump scan.
+	* gcc.dg/ipa/ipacost-1.c: Likewise.
+	* gcc.dg/ipa/ipacost-2.c: Likewise and increased sizes of some
+	functions.
+	* gcc.dg/ipa/ipcp-1.c: New test.
+	* gcc.dg/ipa/ipcp-2.c: Likewise.
+	* gcc.dg/tree-ssa/ipa-cp-1.c: Updated testcase.
+
 2011-07-18  Jakub Jelinek  <jakub@redhat.com>
 
 	PR middle-end/49675

gcc/testsuite/gcc.dg/ipa/ipa-1.c

@@ -24,9 +24,8 @@ int main ()
 }
 
 
-/* { dg-final { scan-ipa-dump-times "versioned function" 2 "cp"  } } */
+/* { dg-final { scan-ipa-dump "Creating a specialized node of f" "cp" } } */
 /* { dg-final { scan-ipa-dump "replacing param a with const 7" "cp"  } } */
-/* { dg-final { scan-ipa-dump "replacing param b with const 7" "cp"  } } */
 /* { dg-final { cleanup-ipa-dump "cp" } } */
 
 

gcc/testsuite/gcc.dg/ipa/ipa-2.c

@@ -22,7 +22,6 @@ int main ()
 }
 
 
-/* { dg-final { scan-ipa-dump-times "versioned function" 2 "cp"  } } */
+/* { dg-final { scan-ipa-dump "Creating a specialized node of f" "cp" } } */
 /* { dg-final { scan-ipa-dump "replacing param a with const 7" "cp"  } } */
-/* { dg-final { scan-ipa-dump "replacing param c with const 3" "cp"  } } */
 /* { dg-final { cleanup-ipa-dump "cp" } } */

gcc/testsuite/gcc.dg/ipa/ipa-3.c

@@ -7,12 +7,12 @@
 
 #include <stdio.h>
 void t(void);
-int g (double b, double c)
+static int g (double b, double c)
 {
   t();
   return (int)(b+c);
 }
-int f (double a)
+static int f (double a)
 {
   if (a > 0)
     g (a, 3.1);
@@ -28,8 +28,9 @@ int main ()
 }
 
 
-/* { dg-final { scan-ipa-dump-times "versioned function" 2 "cp"  } } */
+/* { dg-final { scan-ipa-dump "Creating a specialized node of f" "cp" } } */
 /* { dg-final { scan-ipa-dump "replacing param a with const 7" "cp"  } } */
+/* { dg-final { scan-ipa-dump "Creating a specialized node of g" "cp" } } */
 /* { dg-final { scan-ipa-dump "replacing param b with const 7" "cp"  } } */
 /* { dg-final { scan-ipa-dump "replacing param c with const 3" "cp"  } } */
 /* { dg-final { cleanup-ipa-dump "cp" } } */

gcc/testsuite/gcc.dg/ipa/ipa-4.c

@@ -25,6 +25,6 @@ int main ()
 }
 
 
-/* { dg-final { scan-ipa-dump-times "versioned function" 1 "cp"  } } */
+/* { dg-final { scan-ipa-dump "Creating a specialized node of f" "cp"  } } */
 /* { dg-final { scan-ipa-dump-times "replacing param a with const 7" 1 "cp"  } } */
 /* { dg-final { cleanup-ipa-dump "cp" } } */

gcc/testsuite/gcc.dg/ipa/ipa-5.c

@@ -26,8 +26,7 @@ int main ()
   return 0;
 }
 
-
-/* { dg-final { scan-ipa-dump-times "versioned function" 2 "cp"  } } */
+/* { dg-final { scan-ipa-dump-times "Creating a specialized node" 2 "cp"  } } */
 /* { dg-final { scan-ipa-dump "replacing param c with const 3" "cp"  } } */
 /* { dg-final { scan-ipa-dump "replacing param a with const 7" "cp"  } } */
 /* { dg-final { cleanup-ipa-dump "cp" } } */

gcc/testsuite/gcc.dg/ipa/ipa-7.c

@@ -26,8 +26,8 @@ int main ()
 }
 
 
-/* { dg-final { scan-ipa-dump-times "versioned function" 1 "cp"  } } */
-/* { dg-final { scan-ipa-dump-times "replacing param a with const 7" 1 "cp"  } } */
+/* { dg-final { scan-ipa-dump "Creating a specialized node of f" "cp" } } */
+/* { dg-final { scan-ipa-dump-times "replacing param . with const 7" 1 "cp" } } */
 /* { dg-final { cleanup-ipa-dump "cp" } } */
 
 

gcc/testsuite/gcc.dg/ipa/ipa-8.c

@@ -22,8 +22,9 @@ int main ()
 }
 
 
-/* { dg-final { scan-ipa-dump-times "versioned function" 2 "cp"  } } */
+/* { dg-final { scan-ipa-dump "Creating a specialized node of f" "cp" } } */
 /* { dg-final { scan-ipa-dump "replacing param a with const 7" "cp"  } } */
+/* { dg-final { scan-ipa-dump "Creating a specialized node of g" "cp" } } */
 /* { dg-final { scan-ipa-dump "replacing param b with const 7" "cp"  } } */
 /* { dg-final { cleanup-ipa-dump "cp" } } */
 

gcc/testsuite/gcc.dg/ipa/ipacost-1.c

@@ -51,10 +51,10 @@ main()
   i_can_not_be_propagated_fully2 (array);
 }
 
-/* { dg-final { scan-ipa-dump-times "versioned function i_can_be_propagated_fully2" 1 "cp"  } } */
-/* { dg-final { scan-ipa-dump-times "versioned function i_can_be_propagated_fully " 1 "cp"  } } */
-/* { dg-final { scan-ipa-dump-not "versioned function i_can_not_be_propagated_fully2" "cp"  } } */
-/* { dg-final { scan-ipa-dump-not "versioned function i_can_not_be_propagated_fully " "cp"  } } */
+/* { dg-final { scan-ipa-dump-times "Creating a specialized node of i_can_be_propagated_fully2" 1 "cp"  } } */
+/* { dg-final { scan-ipa-dump-times "Creating a specialized node of i_can_be_propagated_fully/" 1 "cp"  } } */
+/* { dg-final { scan-ipa-dump-not "Creating a specialized node of i_can_not_be_propagated_fully2" "cp"  } } */
+/* { dg-final { scan-ipa-dump-not "Creating a specialized node of i_can_not_be_propagated_fully/" "cp"  } } */
 /* { dg-final { scan-tree-dump-not "i_can_be_propagated_fully " "optimized"  } } */
 /* { dg-final { scan-tree-dump-not "i_can_be_propagated_fully2 " "optimized"  } } */
 /* { dg-final { cleanup-ipa-dump "cp" } } */

gcc/testsuite/gcc.dg/ipa/ipacost-2.c

@@ -40,8 +40,23 @@ i_can_not_be_propagated_fully (int *a)
 int
 i_can_not_be_propagated_fully2 (int *a)
 {
+  int i;
   i_can_not_be_propagated_fully (a);
+  for (i=0;i<50;i++)
+  {
+    t(a[i] + 1);
+    t(a[i+1] + 1);
+    t(a[i+2] + 1);
+    t(a[i+3] + 1);
+  }
   i_can_not_be_propagated_fully (a);
+  for (i=0;i<50;i++)
+  {
+    t(a[i] + 2);
+    t(a[i+1] + 2);
+    t(a[i+2] + 2);
+    t(a[i+3] + 2);
+  }
   i_can_not_be_propagated_fully (a);
 }
 main()
@@ -50,15 +65,15 @@ main()
   i_can_be_propagated_fully2 (array);
   i_can_be_propagated_fully2 (array);
 
-  for (i = 0; i < 100; i++)
+  for (i = 0; i < 7; i++)
     i_can_not_be_propagated_fully2 (array);
   i_can_not_be_propagated_fully2 (array);
 }
 
-/* { dg-final { scan-ipa-dump-times "versioned function i_can_be_propagated_fully2" 1 "cp"  } } */
-/* { dg-final { scan-ipa-dump-times "versioned function i_can_be_propagated_fully " 1 "cp"  } } */
-/* { dg-final { scan-ipa-dump-times "versioned function i_can_not_be_propagated_fully2" 1 "cp"  } } */
-/* { dg-final { scan-ipa-dump-times "versioned function i_can_not_be_propagated_fully " 1 "cp"  } } */
+/* { dg-final { scan-ipa-dump-times "Creating a specialized node of i_can_be_propagated_fully2" 1 "cp"  } } */
+/* { dg-final { scan-ipa-dump-times "Creating a specialized node of i_can_be_propagated_fully/" 1 "cp"  } } */
+/* { dg-final { scan-ipa-dump-not "Creating a specialized node of i_can_not_be_propagated_fully2" "cp"  } } */
+/* { dg-final { scan-ipa-dump-not "Creating a specialized node of i_can_not_be_propagated_fully/" "cp"  } } */
 /* { dg-final { scan-tree-dump-not "i_can_be_propagated_fully \\(" "optimized"  } } */
 /* { dg-final { scan-tree-dump-not "i_can_be_propagated_fully2 \\(" "optimized"  } } */
 /* { dg-final { cleanup-ipa-dump "cp" } } */

gcc/testsuite/gcc.dg/ipa/ipcp-1.c

+/* Test that IPA-CP is able to figure out that poth parameters a are constant 7
+   even though f and h recursively call each other and specialize them
+   accordinly.  */
+
+/* { dg-do compile } */
+/* { dg-options "-O3 -fipa-cp -fipa-cp-clone -fdump-ipa-cp -fno-early-inlining"  } */
+/* { dg-add-options bind_pic_locally } */
+
+extern void use_stuff (int);
+
+static
+int g (int b, int c)
+{
+  int i;
+
+  for (i = 0; i < b; i++)
+    use_stuff (c);
+}
+
+static void f (int a, int x, int z);
+
+static void h (int z, int a)
+{
+  use_stuff (z);
+  f (a, 9, 10);
+
+}
+
+static void
+f (int a, int x, int z)
+{
+  if (z > 1)
+    g (a, x);
+  else
+    h (5, a);
+}
+
+int
+main (int argc, char *argv[])
+{
+  int i;
+  for (i = 0; i < 100; i++)
+    f (7, 8, argc);
+  return 0;
+}
+
+
+/* { dg-final { scan-ipa-dump "Creating a specialized node of f.*for all known contexts" "cp" } } */
+/* { dg-final { scan-ipa-dump "replacing param a with const 7" "cp"  } } */
+/* { dg-final { cleanup-ipa-dump "cp" } } */
+
+

gcc/testsuite/gcc.dg/ipa/ipcp-2.c

+/* { dg-do compile } */
+/* { dg-options "-O3 -fipa-cp -fipa-cp-clone -fdump-ipa-cp -fno-early-inlining"  } */
+/* { dg-add-options bind_pic_locally } */
+
+extern int get_stuff (int);
+extern void do_stuff (int);
+extern void do_stuff2 (int);
+extern void do_other_stuff (void);
+extern int get_element (int, int, int);
+extern int adjust (int, int, int, int);
+
+extern int count;
+
+int
+foo (int s, int p)
+{
+  int c, r = 0;
+
+  for (c = 0 ; c < count; c++)
+    {
+      r += get_stuff (s);
+      /* The following is just something big that can go away.  */
+      if (p != 0)
+	{
+	  int a[64][64];
+	  int i, j, k;
+
+	  for (i = 0; i < 64; i++)
+	    for (j = 0; j < 64; j++)
+	      a[i][j] = get_element (p + c, i, j);
+
+	  for (k = 0; k < 4; k++)
+	    {
+	      r = r / 2;
+
+	      for (i = 1; i < 63; i++)
+		for (j = 62; j > 0; j--)
+		  a[i][j] += adjust (a[i-1][j], a[i][j-1],
+				     a[i+1][j], a[i][j+1]);
+
+	      for (i = 4; i < 64; i += 4)
+		for (j = 4; j < 64; j += 4)
+		  r += a[i][j] / 4;
+	    }
+	}
+    }
+  return r;
+}
+
+int
+bar (int p, int q)
+{
+  if (q > 0)
+    do_stuff (q);
+  else
+    do_stuff (-q);
+
+  if (q % 2)
+    do_stuff2 (2 * q);
+  else
+    do_stuff2 (2 * (q + 1));
+
+  return foo (4, p);
+}
+
+int
+bah (int p, int q)
+{
+  int i, j;
+
+  while (q < -20)
+    q += get_stuff (-q);
+
+  for (i = 0; i < 36; i++)
+    for (j = 0; j < 36; j++)
+      do_stuff (get_stuff (q * i + 2));
+
+  bar (p, q);
+}
+
+int
+top1 (int q)
+{
+  do_other_stuff ();
+  return bah (0, q);
+}
+
+int
+top2 (int q)
+{
+  do_stuff (200);
+  do_other_stuff ();
+  return bah (16, q);
+}
+
+/* { dg-final { scan-ipa-dump-times "Creating a specialized node of foo" 1 "cp" } } */
+/* { dg-final { scan-ipa-dump-times "replacing param p with const 0" 3 "cp"  } } */
+/* { dg-final { scan-ipa-dump "replacing param s with const 4" "cp"  } } */
+/* { dg-final { cleanup-ipa-dump "cp" } } */

gcc/testsuite/gcc.dg/tree-ssa/ipa-cp-1.c

@@ -5,9 +5,13 @@
 int
 very_long_function(int a)
 {
-  return very_long_function (a)/4;
+  if (a > 0)
+    return 2 * a + very_long_function (a)/4;
+  else
+    return 2 * -a + very_long_function (a)/4;
 }
-main()
+
+blah ()
 {
   very_long_function (1);
 }