Enable recursive function versioning

2019-12-02  Feng Xue <fxue@os.amperecomputing.com>

        PR ipa/92133
        * doc/invoke.texi (ipa-cp-max-recursive-depth): Document new option.
        (ipa-cp-min-recursive-probability): Likewise.
        * params.opt (ipa-cp-max-recursive-depth): New.
        (ipa-cp-min-recursive-probability): Likewise.
        * ipa-cp.c (ipcp_lattice<valtype>::add_value): Add two new parameters
        val_p and unlimited.
        (self_recursively_generated_p): New function.
        (get_val_across_arith_op): Likewise.
        (propagate_vals_across_arith_jfunc): Add constant propagation for
        self-recursive function.
        (incorporate_penalties): Do not penalize pure self-recursive function.
        (good_cloning_opportunity_p): Dump node_is_self_scc flag.
        (propagate_constants_topo): Set node_is_self_scc flag for cgraph node.
        (get_info_about_necessary_edges): Relax hotness check for edge to
        self-recursive function.
        * ipa-prop.h (ipa_node_params): Add new field node_is_self_scc.

2019-12-02  Feng Xue  <fxue@os.amperecomputing.com>

        PR ipa/92133
        * gcc.dg/ipa/ipa-clone-2.c: New test.

From-SVN: r278893

gcc/ChangeLog

+2019-12-02  Feng Xue <fxue@os.amperecomputing.com>
+
+	PR ipa/92133
+	* doc/invoke.texi (ipa-cp-max-recursive-depth): Document new option.
+	(ipa-cp-min-recursive-probability): Likewise.
+	* params.opt (ipa-cp-max-recursive-depth): New.
+	(ipa-cp-min-recursive-probability): Likewise.
+	* ipa-cp.c (ipcp_lattice<valtype>::add_value): Add two new parameters
+	val_p and unlimited.
+	(self_recursively_generated_p): New function.
+	(get_val_across_arith_op): Likewise.
+	(propagate_vals_across_arith_jfunc): Add constant propagation for
+	self-recursive function.
+	(incorporate_penalties): Do not penalize pure self-recursive function.
+	(good_cloning_opportunity_p): Dump node_is_self_scc flag.
+	(propagate_constants_topo): Set node_is_self_scc flag for cgraph node.
+	(get_info_about_necessary_edges): Relax hotness check for edge to
+	self-recursive function.
+	* ipa-prop.h (ipa_node_params): Add new field node_is_self_scc.
+
 2019-12-01  Sandra Loosemore  <sandra@codesourcery.com>
 
 	PR target/92499

gcc/doc/invoke.texi

@@ -12035,6 +12035,13 @@ IPA-CP calculates its own score of cloning profitability heuristics
 and performs those cloning opportunities with scores that exceed
 @option{ipa-cp-eval-threshold}.
 
+@item ipa-cp-max-recursive-depth
+Maximum depth of recursive cloning for self-recursive function.
+
+@item ipa-cp-min-recursive-probability
+Recursive cloning only when the probability of call being executed exceeds
+the parameter.
+
 @item ipa-cp-recursion-penalty
 Percentage penalty the recursive functions will receive when they
 are evaluated for cloning.

gcc/ipa-prop.h

@@ -497,6 +497,8 @@ public:
   unsigned node_dead : 1;
   /* Node is involved in a recursion, potentionally indirect.  */
   unsigned node_within_scc : 1;
+  /* Node contains only direct recursion.  */
+  unsigned node_is_self_scc : 1;
   /* Node is calling a private function called only once.  */
   unsigned node_calling_single_call : 1;
   /* False when there is something makes versioning impossible.  */

gcc/params.opt

@@ -198,6 +198,14 @@ Threshold ipa-cp opportunity evaluation that is still considered beneficial to c
 Common Joined UInteger Var(param_ipa_cp_loop_hint_bonus) Init(64) Param
 Compile-time bonus IPA-CP assigns to candidates which make loop bounds or strides known.
 
+-param=ipa-cp-max-recursive-depth=
+Common Joined UInteger Var(param_ipa_cp_max_recursive_depth) Init(8) Param
+Maximum depth of recursive cloning for self-recursive function.
+
+-param=ipa-cp-min-recursive-probability=
+Common Joined UInteger Var(param_ipa_cp_min_recursive_probability) Init(2) Param
+Recursive cloning only when the probability of call being executed exceeds the parameter.
+
 -param=ipa-cp-recursion-penalty=
 Common Joined UInteger Var(param_ipa_cp_recursion_penalty) Init(40) IntegerRange(0, 100) Param
 Percentage penalty the recursive functions will receive when they are evaluated for cloning.

gcc/testsuite/ChangeLog

+2019-12-02  Feng Xue  <fxue@os.amperecomputing.com>
+
+	PR ipa/92133
+	* gcc.dg/ipa/ipa-clone-2.c: New test.
+
 2019-12-01  Sandra Loosemore  <sandra@codesourcery.com>
 
 	PR target/92499

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

+/* { dg-do compile } */
+/* { dg-options "-O3 -fdump-ipa-cp-details -fno-early-inlining --param ipa-cp-max-recursive-depth=8" } */
+
+int fn();
+
+int data[100];
+
+int recur_fn (int i)
+{
+  int j;
+   
+  if (i == 6)
+    {
+      fn();
+      fn();
+      fn();
+      fn();
+      fn();
+      fn();
+      fn();
+      fn();
+      fn();
+      fn();
+      fn();
+      fn();
+      return 10;
+    }
+
+  data[i] = i; 
+
+  for (j = 0; j < 100; j++)
+    recur_fn (i + 1);
+
+  return i; 
+}
+
+int main ()
+{
+  int i;
+
+  for (i = 0; i < 100; i++)
+    recur_fn (1) + recur_fn (-5);
+
+  return 1;
+}
+
+/* { dg-final { scan-ipa-dump-times "Creating a specialized node of recur_fn/\[0-9\]*\\." 12 "cp" } } */