tree-ssa-pre.c (eliminate_dom_walker::before_dom_children): Eliminate edges marked...

2015-08-12  Richard Biener  <rguenther@suse.de>

	* tree-ssa-pre.c (eliminate_dom_walker::before_dom_children):
	Eliminate edges marked as not executable by SCCVN.
	* tree-ssa-sccvn.c: Include gimple-iterator.h.
	(cond_dom_walker): Rename to sccvn_dom_walker.
	(sccvn_dom_walker::before_dom_children): Value-number defs
	of all stmts.
	(run_scc_vn): Remove loop value-numbering all SSA names.
	Drop not visited SSA names to varying.

	* gcc.dg/tree-ssa/ssa-fre-43.c: Adjust.

From-SVN: r226801

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 063513ba0e9c084c8338b01b1d8a0c36349dd101..206dc3aa44df0d7890a41af26aefd71d17694f7c 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,14 @@
+2015-08-12  Richard Biener  <rguenther@suse.de>
+
+       * tree-ssa-pre.c (eliminate_dom_walker::before_dom_children):
+       Eliminate edges marked as not executable by SCCVN.
+       * tree-ssa-sccvn.c: Include gimple-iterator.h.
+       (cond_dom_walker): Rename to sccvn_dom_walker.
+       (sccvn_dom_walker::before_dom_children): Value-number defs
+       of all stmts.
+       (run_scc_vn): Remove loop value-numbering all SSA names.
+       Drop not visited SSA names to varying.
+
 2015-08-11  Trevor Saunders  <tbsaunde@tbsaunde.org>
 
        * compare-elim.c, dce.c, dse.c, gimple-ssa-isolate-paths.c,

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 8fa89f2fe7766d352221290e24e9e5a6519d48e7..7bb63a5f4ac2aee7f7c770a2383cb54527ac4a31 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2015-08-12  Richard Biener  <rguenther@suse.de>
+
+       * gcc.dg/tree-ssa/ssa-fre-43.c: Adjust.
+
 2015-08-12  Tom de Vries  <tom@codesourcery.com>
 
        PR testsuite/67175

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-43.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-43.c
index af6adbda43e4b580cb1ddcaaca25ab37a2211b35..1a837666c256c964d47d835f9355aeb0ba5a0667 100644 (file)
--- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-43.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-43.c
@@ -21,8 +21,8 @@ L10:
   goto L10;
 }
 
-/* We should remove 15 dead loads, fully propagating their replacements
-   with exactly 4 loads and 4 stores from/to E remaining.  */
+/* We should remove 15 dead loads and some related stmts, fully propagating
+   their replacements with exactly 4 loads and 4 stores from/to E remaining.  */
 
-/* { dg-final { scan-tree-dump-times "Removing dead stmt" 15 "fre1" } } */
+/* { dg-final { scan-tree-dump-times "Removing dead stmt" 19 "fre1" } } */
 /* { dg-final { scan-tree-dump-not "Not changing value number" "fre1" } } */

diff --git a/gcc/tree-ssa-pre.c b/gcc/tree-ssa-pre.c
index 041cb78dc4991bd21fadb39fbedef430be01ed6a..697958def0c994fb1fef012de497827af89a3482 100644 (file)
--- a/gcc/tree-ssa-pre.c
+++ b/gcc/tree-ssa-pre.c
@@ -4291,7 +4291,31 @@ eliminate_dom_walker::before_dom_children (basic_block b)
               el_to_remove.safe_push (stmt);
              continue;
             }
-        }
+       }
+
+      /* If this is a control statement value numbering left edges
+        unexecuted on force the condition in a way consistent with
+        that.  */
+      if (gcond *cond = dyn_cast <gcond *> (stmt))
+       {
+         if ((EDGE_SUCC (b, 0)->flags & EDGE_EXECUTABLE)
+             ^ (EDGE_SUCC (b, 1)->flags & EDGE_EXECUTABLE))
+           {
+              if (dump_file && (dump_flags & TDF_DETAILS))
+                {
+                  fprintf (dump_file, "Removing unexecutable edge from ");
+                  print_gimple_stmt (dump_file, stmt, 0, 0);
+                }
+             if (((EDGE_SUCC (b, 0)->flags & EDGE_TRUE_VALUE) != 0)
+                 == ((EDGE_SUCC (b, 0)->flags & EDGE_EXECUTABLE) != 0))
+               gimple_cond_make_true (cond);
+             else
+               gimple_cond_make_false (cond);
+             update_stmt (cond);
+             el_todo |= TODO_cleanup_cfg;
+             continue;
+           }
+       }
 
       bool can_make_abnormal_goto = stmt_can_make_abnormal_goto (stmt);
       bool was_noreturn = (is_gimple_call (stmt)

diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c
index ab4b1100b8ce5c166545520c84c724d8a294c823..eca0d44cdaf8a5915735ec130b4969f30c08af1b 100644 (file)
--- a/gcc/tree-ssa-sccvn.c
+++ b/gcc/tree-ssa-sccvn.c
@@ -57,6 +57,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "tree-cfg.h"
 #include "domwalk.h"
 #include "cgraph.h"
+#include "gimple-iterator.h"
 
 /* This algorithm is based on the SCC algorithm presented by Keith
    Cooper and L. Taylor Simpson in "SCC-Based Value numbering"
@@ -4277,18 +4278,20 @@ set_hashtable_value_ids (void)
     set_value_id_for_result (vr->result, &vr->value_id);
 }
 
-class cond_dom_walker : public dom_walker
+class sccvn_dom_walker : public dom_walker
 {
 public:
-  cond_dom_walker () : dom_walker (CDI_DOMINATORS), fail (false) {}
+  sccvn_dom_walker () : dom_walker (CDI_DOMINATORS), fail (false) {}
 
   virtual void before_dom_children (basic_block);
 
   bool fail;
 };
 
+/* Value number all statements in BB.  */
+
 void
-cond_dom_walker::before_dom_children (basic_block bb)
+sccvn_dom_walker::before_dom_children (basic_block bb)
 {
   edge e;
   edge_iterator ei;
@@ -4317,6 +4320,34 @@ cond_dom_walker::before_dom_children (basic_block bb)
       return;
     }
 
+  /* Value-number all defs in the basic-block.  */
+  for (gphi_iterator gsi = gsi_start_phis (bb);
+       !gsi_end_p (gsi); gsi_next (&gsi))
+    {
+      gphi *phi = gsi.phi ();
+      tree res = PHI_RESULT (phi);
+      if (!VN_INFO (res)->visited
+         && !DFS (res))
+       {
+         fail = true;
+         return;
+       }
+    }
+  for (gimple_stmt_iterator gsi = gsi_start_bb (bb);
+       !gsi_end_p (gsi); gsi_next (&gsi))
+    {
+      ssa_op_iter i;
+      tree op;
+      FOR_EACH_SSA_TREE_OPERAND (op, gsi_stmt (gsi), i, SSA_OP_ALL_DEFS)
+       if (!VN_INFO (op)->visited
+           && !DFS (op))
+         {
+           fail = true;
+           return;
+         }
+    }
+
+  /* Finally look at the last stmt.  */
   gimple stmt = last_stmt (bb);
   if (!stmt)
     return;
@@ -4329,8 +4360,7 @@ cond_dom_walker::before_dom_children (basic_block bb)
 
   if (dump_file && (dump_flags & TDF_DETAILS))
     {
-      fprintf (dump_file, "Value-numbering operands of stmt ending BB %d: ",
-              bb->index);
+      fprintf (dump_file, "Visiting stmt ending BB %d: ", bb->index);
       print_gimple_stmt (dump_file, stmt, 0, 0);
     }
 
@@ -4338,12 +4368,8 @@ cond_dom_walker::before_dom_children (basic_block bb)
   ssa_op_iter i;
   tree op;
   FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
-    if (VN_INFO (op)->visited == false
-       && !DFS (op))
-      {
-       fail = true;
-       return;
-      }
+    gcc_assert (VN_INFO (op)->visited
+               || SSA_NAME_IS_DEFAULT_DEF (op));
 
   /* ???  We can even handle stmts with outgoing EH or ABNORMAL edges
      if value-numbering can prove they are not reachable.  Handling
@@ -4427,9 +4453,9 @@ run_scc_vn (vn_lookup_kind default_vn_walk_kind_)
        e->flags |= EDGE_EXECUTABLE;
     }
 
-  /* Walk all blocks in dominator order, value-numbering the last stmts
-     SSA uses and decide whether outgoing edges are not executable.  */
-  cond_dom_walker walker;
+  /* Walk all blocks in dominator order, value-numbering stmts
+     SSA defs and decide whether outgoing edges are not executable.  */
+  sccvn_dom_walker walker;
   walker.walk (ENTRY_BLOCK_PTR_FOR_FN (cfun));
   if (walker.fail)
     {
@@ -4437,22 +4463,8 @@ run_scc_vn (vn_lookup_kind default_vn_walk_kind_)
       return false;
     }
 
-  /* Value-number remaining SSA names.  */
-  for (i = 1; i < num_ssa_names; ++i)
-    {
-      tree name = ssa_name (i);
-      if (name
-         && VN_INFO (name)->visited == false
-         && !has_zero_uses (name))
-       if (!DFS (name))
-         {
-           free_scc_vn ();
-           return false;
-         }
-    }
-
-  /* Initialize the value ids.  */
-
+  /* Initialize the value ids and prune out remaining VN_TOPs
+     from dead code.  */
   for (i = 1; i < num_ssa_names; ++i)
     {
       tree name = ssa_name (i);
@@ -4460,6 +4472,8 @@ run_scc_vn (vn_lookup_kind default_vn_walk_kind_)
       if (!name)
        continue;
       info = VN_INFO (name);
+      if (!info->visited)
+       info->valnum = name;
       if (info->valnum == name
          || info->valnum == VN_TOP)
        info->value_id = get_next_value_id ();