Generalized value pass-through for self-recusive function (PR ipa/93203)
authorFeng Xue <fxue@os.amperecomputing.com>
Tue, 21 Jan 2020 12:53:38 +0000 (20:53 +0800)
committerFeng Xue <fxue@os.amperecomputing.com>
Mon, 10 Feb 2020 04:31:09 +0000 (12:31 +0800)
Besides simple pass-through (aggregate) jump function, arithmetic (aggregate)
jump function could also bring same (aggregate) value as parameter passed-in
for self-feeding recursive call.  For example,

      f1 (int i)    /*  normal jump function */
         {
            f1 (i & 1);
         }

Suppose i is 0, recursive propagation via (i & 1) also gets 0, which
can be seen as a simple pass-through of i.

      f2 (int *p)  /* aggregate jump function */
         {
            int t = *p & 1;
            f2 (&t);
         }
Likewise, if *p is 0, (*p & 1) is also 0, and &t is an aggregate simple
pass-through of p.

2020-02-10  Feng Xue  <fxue@os.amperecomputing.com>

        PR ipa/93203
        * ipa-cp.c (ipcp_lattice::add_value): Add source with same call edge
        but different source value.
        (adjust_callers_for_value_intersection): New function.
        (gather_edges_for_value): Adjust order of callers to let a
        non-self-recursive caller be the first element.
        (self_recursive_pass_through_p): Add a new parameter "simple", and
        check generalized self-recursive pass-through jump function.
        (self_recursive_agg_pass_through_p): Likewise.
        (find_more_scalar_values_for_callers_subset): Compute value from
        pass-through jump function for self-recursive.
        (intersect_with_plats): Cleanup previous implementation code for value
        itersection with self-recursive call edge.
        (intersect_with_agg_replacements): Likewise.
        (intersect_aggregates_with_edge): Deduce value from pass-through jump
        function for self-recursive call edge.  Cleanup previous implementation
        code for value intersection with self-recursive call edge.
        (decide_whether_version_node): Remove dead callers and adjust order
        to let a non-self-recursive caller be the first element.

        PR ipa/93203
        * g++.dg/ipa/pr93203.C: New test.

gcc/ChangeLog
gcc/ipa-cp.c
gcc/testsuite/ChangeLog
gcc/testsuite/g++.dg/ipa/pr93203.C [new file with mode: 0644]
gcc/testsuite/gcc.dg/ipa/ipcp-1.c

index feb2d06..fa3cbb8 100644 (file)
@@ -1,3 +1,25 @@
+2020-02-10  Feng Xue  <fxue@os.amperecomputing.com>
+
+       PR ipa/93203
+       * ipa-cp.c (ipcp_lattice::add_value): Add source with same call edge
+       but different source value.
+       (adjust_callers_for_value_intersection): New function.
+       (gather_edges_for_value): Adjust order of callers to let a
+       non-self-recursive caller be the first element.
+       (self_recursive_pass_through_p): Add a new parameter "simple", and
+       check generalized self-recursive pass-through jump function.
+       (self_recursive_agg_pass_through_p): Likewise.
+       (find_more_scalar_values_for_callers_subset): Compute value from
+       pass-through jump function for self-recursive.
+       (intersect_with_plats): Cleanup previous implementation code for value
+       itersection with self-recursive call edge.
+       (intersect_with_agg_replacements): Likewise.
+       (intersect_aggregates_with_edge): Deduce value from pass-through jump
+       function for self-recursive call edge.  Cleanup previous implementation
+       code for value intersection with self-recursive call edge.
+       (decide_whether_version_node): Remove dead callers and adjust order
+       to let a non-self-recursive caller be the first element.
+
 2020-02-09  Uroš Bizjak  <ubizjak@gmail.com>
 
        * recog.c: Move pass_split_before_sched2 code in front of
index e762abb..4f5b72e 100644 (file)
@@ -1850,7 +1850,7 @@ ipcp_lattice<valtype>::add_value (valtype newval, cgraph_edge *cs,
          {
            ipcp_value_source<valtype> *s;
            for (s = val->sources; s; s = s->next)
-             if (s->cs == cs)
+             if (s->cs == cs && s->val == src_val)
                break;
            if (s)
              return false;
@@ -4204,6 +4204,33 @@ get_info_about_necessary_edges (ipcp_value<valtype> *val, cgraph_node *dest,
   return hot;
 }
 
+/* Given a NODE, and a set of its CALLERS, try to adjust order of the callers
+   to let a non-self-recursive caller be the first element.  Thus, we can
+   simplify intersecting operations on values that arrive from all of these
+   callers, especially when there exists self-recursive call.  Return true if
+   this kind of adjustment is possible.  */
+
+static bool
+adjust_callers_for_value_intersection (vec<cgraph_edge *> callers,
+                                      cgraph_node *node)
+{
+  for (unsigned i = 0; i < callers.length (); i++)
+    {
+      cgraph_edge *cs = callers[i];
+
+      if (cs->caller != node)
+       {
+         if (i > 0)
+           {
+             callers[i] = callers[0];
+             callers[0] = cs;
+           }
+         return true;
+       }
+    }
+  return false;
+}
+
 /* Return a vector of incoming edges that do bring value VAL to node DEST.  It
    is assumed their number is known and equal to CALLER_COUNT.  */
 
@@ -4227,6 +4254,9 @@ gather_edges_for_value (ipcp_value<valtype> *val, cgraph_node *dest,
        }
     }
 
+  if (caller_count > 1)
+    adjust_callers_for_value_intersection (ret, dest);
+
   return ret;
 }
 
@@ -4238,7 +4268,6 @@ get_replacement_map (class ipa_node_params *info, tree value, int parm_num)
 {
   struct ipa_replace_map *replace_map;
 
-
   replace_map = ggc_alloc<ipa_replace_map> ();
   if (dump_file)
     {
@@ -4589,36 +4618,40 @@ create_specialized_node (struct cgraph_node *node,
 }
 
 /* Return true, if JFUNC, which describes a i-th parameter of call CS, is a
-   simple no-operation pass-through function to itself.  */
+   pass-through function to itself.  When SIMPLE is true, further check if
+   JFUNC is a simple no-operation pass-through.  */
 
 static bool
-self_recursive_pass_through_p (cgraph_edge *cs, ipa_jump_func *jfunc, int i)
+self_recursive_pass_through_p (cgraph_edge *cs, ipa_jump_func *jfunc, int i,
+                              bool simple = true)
 {
   enum availability availability;
   if (cs->caller == cs->callee->function_symbol (&availability)
       && availability > AVAIL_INTERPOSABLE
       && jfunc->type == IPA_JF_PASS_THROUGH
-      && ipa_get_jf_pass_through_operation (jfunc) == NOP_EXPR
+      && (!simple || ipa_get_jf_pass_through_operation (jfunc) == NOP_EXPR)
       && ipa_get_jf_pass_through_formal_id (jfunc) == i)
     return true;
   return false;
 }
 
 /* Return true, if JFUNC, which describes a part of an aggregate represented
-   or pointed to by the i-th parameter of call CS, is a simple no-operation
-   pass-through function to itself.  */
+   or pointed to by the i-th parameter of call CS, is a pass-through function
+   to itself.  When SIMPLE is true, further check if JFUNC is a simple
+   no-operation pass-through.  */
 
 static bool
 self_recursive_agg_pass_through_p (cgraph_edge *cs, ipa_agg_jf_item *jfunc,
-                                  int i)
+                                  int i, bool simple = true)
 {
   enum availability availability;
   if (cs->caller == cs->callee->function_symbol (&availability)
       && availability > AVAIL_INTERPOSABLE
       && jfunc->jftype == IPA_JF_LOAD_AGG
       && jfunc->offset == jfunc->value.load_agg.offset
-      && jfunc->value.pass_through.operation == NOP_EXPR
-      && jfunc->value.pass_through.formal_id == i)
+      && (!simple || jfunc->value.pass_through.operation == NOP_EXPR)
+      && jfunc->value.pass_through.formal_id == i
+      && useless_type_conversion_p (jfunc->value.load_agg.type, jfunc->type))
     return true;
   return false;
 }
@@ -4650,9 +4683,6 @@ find_more_scalar_values_for_callers_subset (struct cgraph_node *node,
          struct ipa_jump_func *jump_func;
          tree t;
 
-         if (IPA_NODE_REF (cs->caller) && IPA_NODE_REF (cs->caller)->node_dead)
-           continue;
-
          if (!IPA_EDGE_REF (cs)
              || i >= ipa_get_cs_argument_count (IPA_EDGE_REF (cs))
              || (i == 0
@@ -4662,10 +4692,30 @@ find_more_scalar_values_for_callers_subset (struct cgraph_node *node,
              break;
            }
          jump_func = ipa_get_ith_jump_func (IPA_EDGE_REF (cs), i);
-         if (self_recursive_pass_through_p (cs, jump_func, i))
-           continue;
 
-         t = ipa_value_from_jfunc (IPA_NODE_REF (cs->caller), jump_func, type);
+         /* Besides simple pass-through jump function, arithmetic jump
+            function could also introduce argument-direct-pass-through for
+            self-feeding recursive call.  For example,
+
+               fn (int i)
+               {
+                 fn (i & 1);
+               }
+
+            Given that i is 0, recursive propagation via (i & 1) also gets
+            0.  */
+         if (self_recursive_pass_through_p (cs, jump_func, i, false))
+           {
+             gcc_assert (newval);
+             t = ipa_get_jf_arith_result (
+                               ipa_get_jf_pass_through_operation (jump_func),
+                               newval,
+                               ipa_get_jf_pass_through_operand (jump_func),
+                               type);
+           }
+         else
+           t = ipa_value_from_jfunc (IPA_NODE_REF (cs->caller), jump_func,
+                                     type);
          if (!t
              || (newval
                  && !values_equal_for_ipcp_p (t, newval))
@@ -4814,19 +4864,12 @@ intersect_with_plats (class ipcp_param_lattices *plats,
            break;
          if (aglat->offset - offset == item->offset)
            {
-             gcc_checking_assert (item->value);
              if (aglat->is_single_const ())
                {
                  tree value = aglat->values->value;
 
                  if (values_equal_for_ipcp_p (item->value, value))
                    found = true;
-                 else if (item->value == error_mark_node)
-                   {
-                     /* Replace unknown place holder value with real one.  */
-                     item->value = value;
-                     found = true;
-                   }
                }
              break;
            }
@@ -4895,12 +4938,6 @@ intersect_with_agg_replacements (struct cgraph_node *node, int index,
            {
              if (values_equal_for_ipcp_p (item->value, av->value))
                found = true;
-             else if (item->value == error_mark_node)
-               {
-                 /* Replace place holder value with real one.  */
-                 item->value = av->value;
-                 found = true;
-               }
              break;
            }
        }
@@ -5005,31 +5042,16 @@ intersect_aggregates_with_edge (struct cgraph_edge *cs, int index,
        for (unsigned i = 0; i < jfunc->agg.items->length (); i++)
          {
            struct ipa_agg_jf_item *agg_item = &(*jfunc->agg.items)[i];
-           struct ipa_agg_value agg_value;
-
-           if (self_recursive_agg_pass_through_p (cs, agg_item, index))
-             {
-               /* For a self-recursive call, if aggregate jump function is a
-                  simple pass-through, the exact value that it stands for is
-                  not known at this point, which must comes from other call
-                  sites.  But we still need to add a place holder in value
-                  sets to indicate it, here we use error_mark_node to
-                  represent the special unknown value, which will be replaced
-                  with real one during later intersecting operations.  */
-               agg_value.value = error_mark_node;
-             }
-           else
+           tree value = ipa_agg_value_from_node (caller_info, cs->caller,
+                                                 agg_item);
+           if (value)
              {
-               tree value = ipa_agg_value_from_node (caller_info, cs->caller,
-                                                     agg_item);
-               if (!value)
-                 continue;
+               struct ipa_agg_value agg_value;
 
                agg_value.value = value;
+               agg_value.offset = agg_item->offset;
+               inter.safe_push (agg_value);
              }
-
-           agg_value.offset = agg_item->offset;
-           inter.safe_push (agg_value);
          }
       else
        FOR_EACH_VEC_ELT (inter, k, item)
@@ -5050,25 +5072,32 @@ intersect_aggregates_with_edge (struct cgraph_edge *cs, int index,
                  {
                    tree value;
 
-                   if (self_recursive_agg_pass_through_p (cs, ti, index))
-                     {
-                       /* A simple aggregate pass-through in self-recursive
-                          call should lead to same value.  */
-                       found = true;
-                     }
-                   else if ((value = ipa_agg_value_from_node (caller_info,
-                                                            cs->caller, ti)))
-                     {
-                       if (values_equal_for_ipcp_p (item->value, value))
-                         found = true;
-                       else if (item->value == error_mark_node)
-                         {
-                           /* Replace unknown place holder value with real
-                              one.  */
-                           item->value = value;
-                           found = true;
-                         }
-                     }
+                   /* Besides simple pass-through aggregate jump function,
+                      arithmetic aggregate jump function could also bring
+                      same aggregate value as parameter passed-in for
+                      self-feeding recursive call.  For example,
+
+                        fn (int *i)
+                          {
+                            int j = *i & 1;
+                            fn (&j);
+                          }
+
+                      Given that *i is 0, recursive propagation via (*i & 1)
+                      also gets 0.  */
+                   if (self_recursive_agg_pass_through_p (cs, ti, index,
+                                                          false))
+                     value = ipa_get_jf_arith_result (
+                                       ti->value.pass_through.operation,
+                                       item->value,
+                                       ti->value.pass_through.operand,
+                                       ti->type);
+                   else
+                     value = ipa_agg_value_from_node (caller_info,
+                                                      cs->caller, ti);
+
+                   if (value && values_equal_for_ipcp_p (item->value, value))
+                     found = true;
                    break;
                  }
                l++;
@@ -5144,9 +5173,6 @@ find_aggregate_values_for_callers_subset (struct cgraph_node *node,
          if (!item->value)
            continue;
 
-         /* All values must be real values, not unknown place holders.  */
-         gcc_assert (item->value != error_mark_node);
-
          v = ggc_alloc<ipa_agg_replacement_value> ();
          v->index = i;
          v->offset = item->offset;
@@ -5542,13 +5568,33 @@ decide_whether_version_node (struct cgraph_node *node)
   if (info->do_clone_for_all_contexts)
     {
       struct cgraph_node *clone;
-      vec<cgraph_edge *> callers;
+      vec<cgraph_edge *> callers = node->collect_callers ();
+
+      for (int i = callers.length () - 1; i >= 0; i--)
+       {
+         cgraph_edge *cs = callers[i];
+         class ipa_node_params *caller_info = IPA_NODE_REF (cs->caller);
+
+         if (caller_info && caller_info->node_dead)
+           callers.unordered_remove (i);
+       }
+
+      if (!adjust_callers_for_value_intersection (callers, node))
+       {
+         /* If node is not called by anyone, or all its caller edges are
+            self-recursive, the node is not really be in use, no need to
+            do cloning.  */
+         callers.release ();
+         known_csts.release ();
+         known_contexts.release ();
+         info->do_clone_for_all_contexts = false;
+         return ret;
+       }
 
       if (dump_file)
        fprintf (dump_file, " - Creating a specialized node of %s "
                 "for all known contexts.\n", node->dump_name ());
 
-      callers = node->collect_callers ();
       find_more_scalar_values_for_callers_subset (node, known_csts, callers);
       find_more_contexts_for_caller_subset (node, &known_contexts, callers);
       ipa_agg_replacement_value *aggvals
index e02d3e8..fddd015 100644 (file)
@@ -1,3 +1,8 @@
+2020-02-10  Feng Xue  <fxue@os.amperecomputing.com>
+
+       PR ipa/93203
+       * g++.dg/ipa/pr93203.C: New test.
+
 2020-02-09  Uroš Bizjak  <ubizjak@gmail.com>
 
        * gcc.target/i386/pr91333.c (dg-do): Fix target selector.
diff --git a/gcc/testsuite/g++.dg/ipa/pr93203.C b/gcc/testsuite/g++.dg/ipa/pr93203.C
new file mode 100644 (file)
index 0000000..b4cd690
--- /dev/null
@@ -0,0 +1,95 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -w -std=gnu++11" } */
+
+class a {
+public:
+  a(char *);
+};
+class ad {
+public:
+  ad(a *);
+};
+class b {};
+using ah = class ak {
+  using al = char;
+
+public:
+  ak(b) : ak(0) {}
+  ak an() { return ap & 1; }
+  al ap;
+  ak(al af) : ap(af) {}
+};
+struct at {
+  ah au;
+  int av;
+  char aw;
+  char ax;
+};
+class az {
+public:
+  struct ba {
+    void bb(ak am) {
+      ak bc = am.an();
+      bb(bc);
+    }
+  };
+  void bd(ak am) { be.bb(am); }
+  ba be;
+};
+class bg {
+public:
+  int bh;
+  at bi;
+};
+int bj;
+int *bk;
+int c;
+class bl {
+  bool bm();
+  bg bn;
+  az bo;
+  int e;
+  int bq;
+};
+class bs {
+public:
+  bs(int *, ah *, char *, char *, int);
+};
+template < typename bt > class bu : bs {
+  using bv = typename bt::bv;
+
+public:
+  template < typename... bx >
+  bu(a *by, int *bz, at body, bx...)
+      : bs(bz, &body.au, &body.aw, &body.ax, body.av), ca(bx()...), cb(by),
+        cc(by), cd(by), ce(by) {}
+  void cf() {
+    auto cg = ch();
+    auto ci = *cj();
+    ca.ck(this, cg, &ci);
+  }
+  bt ca;
+  ad cb;
+  ad cc;
+  ad cd;
+  ad ce;
+  bv *cj();
+  bv ch();
+};
+class cl {
+public:
+  using bv = struct {};
+  cl(az *, int, int, int, int, a *, int, int **);
+  void ck(bs *, bv, bv *) {
+    b d;
+    ak ci(d);
+    bo.bd(ci);
+  }
+  az bo;
+};
+bool bl::bm() {
+  a by("");
+  bu< cl > cn(&by, &bj, bn.bi, &bo, c, bn.bh, e, 0, &by, bq, &bk);
+  cn.cf();
+}
+
index 952694d..baa9c97 100644 (file)
@@ -45,7 +45,7 @@ main (int argc, char *argv[])
 }
 
 
-/* { dg-final { scan-ipa-dump "Creating a specialized node of f.*for all known contexts" "cp" } } */
+/* { dg-final { scan-ipa-dump "Creating a specialized node of f" "cp" } } */
 /* { dg-final { scan-ipa-dump "replacing param .0 a with const 7" "cp"  } } */