revert: re PR lto/66752 (spec2000 255.vortex performance compiled with GCC is ~20% lower than with CLANG)

Revert:
        PR lto/66752
        * tree-ssa-threadedge.c (simplify_conrol_stmt_condition): If we are
        unable to find X NE 0 in the tables, return X as the simplified
        condition.
        (fsm_find_control_statement_thread_paths): If nodes in NEXT_PATH are
        in VISISTED_BBS, then return failure.  Else add nodes from NEXT_PATH
        to VISISTED_BBS.  */
        * tree-ssa-threadupdate.c (duplicate_thread_path): Fix up edge flags
        after removing the control flow statement and unnecessary edges.

    testsuite/
        PR lto/66752
        * gcc.dg/tree-ssa/pr66752-2.c: New test.
        * gcc.dg/torture/pr66752-1.c: New test
        * g++.dg/torture/pr66752-2.C: New test.

From-SVN: r226206

7 files changed, 21 insertions, 157 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4af1180..eebe69d 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,16 @@
+2015-07-25  Jeff Law  <law@redhat.com>
+
+	Revert:
+	PR lto/66752
+	* tree-ssa-threadedge.c (simplify_conrol_stmt_condition): If we are
+	unable to find X NE 0 in the tables, return X as the simplified
+	condition.
+	(fsm_find_control_statement_thread_paths): If nodes in NEXT_PATH are
+	in VISISTED_BBS, then return failure.  Else add nodes from NEXT_PATH
+	to VISISTED_BBS.  */
+	* tree-ssa-threadupdate.c (duplicate_thread_path): Fix up edge flags
+	after removing the control flow statement and unnecessary edges.
+
 2015-07-25  David Edelsohn  <dje.gcc@gmail.com>
 
 	Revert:
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a05f16c..8cb2011 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2015-07-25  Jeff Law  <law@redhat.com>
+
+	Revert:
+	PR lto/66752
+	* gcc.dg/tree-ssa/pr66752-2.c: New test.
+	* gcc.dg/torture/pr66752-1.c: New test
+	* g++.dg/torture/pr66752-2.C: New test.
+
 2015-07-25  David Edelsohn  <dje.gcc@gmail.com>
 
 	Revert:
diff --git a/gcc/testsuite/g++.dg/torture/pr66752-2.C b/gcc/testsuite/g++.dg/torture/pr66752-2.C
deleted file mode 100644
index 96d3fe9..0000000
--- a/gcc/testsuite/g++.dg/torture/pr66752-2.C
+++ /dev/null
@@ -1,60 +0,0 @@
-/* { dg-do compile } */
-extern "C"
-{
-  typedef struct _IO_FILE FILE;
-  extern int fprintf (FILE * __restrict __stream,
-		      const char *__restrict __format, ...);
-}
-typedef union tree_node *tree;
-class ipa_polymorphic_call_context
-{
-};
-class ipcp_value_base
-{
-};
-template < typename valtype > class ipcp_value:public ipcp_value_base
-{
-public:valtype value;
-  ipcp_value *next;
-};
-
-template < typename valtype > class ipcp_lattice
-{
-public:ipcp_value < valtype > *values;
-  void print (FILE * f, bool dump_sources, bool dump_benefits);
-};
-
-class ipcp_param_lattices
-{
-public:ipcp_lattice < tree > itself;
-  ipcp_lattice < ipa_polymorphic_call_context > ctxlat;
-};
-template < typename valtype > void ipcp_lattice < valtype >::print (FILE * f,
-								    bool
-								    dump_sources,
-								    bool
-								    dump_benefits)
-{
-  ipcp_value < valtype > *val;
-  bool prev = false;
-  for (val = values; val; val = val->next)
-    {
-      if (dump_benefits && prev)
-	fprintf (f, "               ");
-      else if (!dump_benefits && prev)
-	fprintf (f, ", ");
-      else
-	prev = true;
-      if (dump_sources)
-	fprintf (f, "]");
-      if (dump_benefits)
-	fprintf (f, "shit");
-    }
-}
-
-void
-print_all_lattices (FILE * f, bool dump_sources, bool dump_benefits)
-{
-  struct ipcp_param_lattices *plats;
-  plats->ctxlat.print (f, dump_sources, dump_benefits);
-}
diff --git a/gcc/testsuite/gcc.dg/torture/pr66752-1.c b/gcc/testsuite/gcc.dg/torture/pr66752-1.c
deleted file mode 100644
index a742555..0000000
--- a/gcc/testsuite/gcc.dg/torture/pr66752-1.c
+++ /dev/null
@@ -1,27 +0,0 @@
-/* { dg-do compile } */
-
-typedef unsigned int size_t;
-struct fde_vector
-{
-  size_t count;
-  const struct dwarf_fde *array[];
-};
-struct object;
-typedef struct dwarf_fde fde;
-typedef int (*fde_compare_t) (struct object *, const fde *, const fde *);
-void
-fde_merge (struct object *ob, fde_compare_t fde_compare,
-	   struct fde_vector *v1, struct fde_vector *v2)
-{
-  size_t i1, i2;
-  const fde *fde2;
-  do
-    {
-      i2--;
-      while (i1 > 0 && fde_compare (ob, v1->array[i1 - 1], fde2) > 0)
-	{
-	  i1--;
-	}
-    }
-  while (i2 > 0);
-}
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr66752-3.c b/gcc/testsuite/gcc.dg/tree-ssa/pr66752-3.c
deleted file mode 100644
index f15b598..0000000
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr66752-3.c
+++ /dev/null
@@ -1,39 +0,0 @@
-/* { dg-do compile } */
-/* { dg-options "-O2 -fdump-tree-dom1-details -fdump-tree-optimized" } */
-
-extern int status, pt;
-extern int count;
-void
-foo (int N, int c, int b, int *a)
-{
-  int i, flag;
-  i = b -1;
-  flag = 1;
-  if (status && i < N && a[i] == b) {
-    N--;
-    flag = 0;
-   if (pt)
-     count++;
-  }
-  else    
-    for (i = -1, flag = 1; ++i < N && flag;)
-      if (a[i] == b)
-        {
-          --N;
-          flag = 0;
-          if (i < N)
-            a[i] = a[N];
-           else
-            a[i] = 0;
-          if (pt)
-            count++;
-        }
- if(status && flag)
-   pt--;
-}
-
-/* There are 3 FSM jump threading opportunities.  */
-/* { dg-final { scan-tree-dump-times "FSM" 3 "dom1"} } */
-
-/* There should be no assignments or references to FLAG.  */
-/* { dg-final { scan-tree-dump-not "flag" "optimized"} } */
diff --git a/gcc/tree-ssa-threadedge.c b/gcc/tree-ssa-threadedge.c
index 5228951..7164122 100644
--- a/gcc/tree-ssa-threadedge.c
+++ b/gcc/tree-ssa-threadedge.c
@@ -553,16 +553,6 @@ simplify_control_stmt_condition (edge e,
           || !is_gimple_min_invariant (cached_lhs))
         cached_lhs = (*simplify) (dummy_cond, stmt);
 
-      /* If we were just testing that an integral type was != 0, and that
-	 failed, just return the first operand.  This gives the FSM code a
-	 chance to optimize the path.  */
-      if (cached_lhs == NULL
-	  && cond_code == NE_EXPR
-	  && INTEGRAL_TYPE_P (TREE_TYPE (op0))
-	  && TREE_CODE (op0) == SSA_NAME
-	  && integer_zerop (op1))
-	return op0;
-
       return cached_lhs;
     }
 
@@ -984,21 +974,6 @@ fsm_find_control_statement_thread_paths (tree expr,
 	  return;
 	}
 
-      /* Make sure we haven't already visited any of the nodes in
- 	 NEXT_PATH.  Don't add them here to avoid pollution.  */
-      for (unsigned int i = 0; i < next_path->length () - 1; i++)
-	{
-	  if (visited_bbs->contains ((*next_path)[i]))
-	    {
-	      vec_free (next_path);
-	      return;
-	    }
-	}
-
-      /* Now add the nodes to VISISTED_BBS.  */
-      for (unsigned int i = 0; i < next_path->length () - 1; i++)
-	visited_bbs->add ((*next_path)[i]);
-
       /* Append all the nodes from NEXT_PATH to PATH.  */
       vec_safe_splice (path, next_path);
       next_path_length = next_path->length ();
diff --git a/gcc/tree-ssa-threadupdate.c b/gcc/tree-ssa-threadupdate.c
index 62937b4..31ddf25 100644
--- a/gcc/tree-ssa-threadupdate.c
+++ b/gcc/tree-ssa-threadupdate.c
@@ -2480,12 +2480,6 @@ duplicate_thread_path (edge entry, edge exit,
 
   /* Remove the last branch in the jump thread path.  */
   remove_ctrl_stmt_and_useless_edges (region_copy[n_region - 1], exit->dest);
-
-  /* And fixup the flags on the single remaining edge.  */
-  edge fix_e = find_edge (region_copy[n_region - 1], exit->dest);
-  fix_e->flags &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE | EDGE_ABNORMAL);
-  fix_e->flags |= EDGE_FALLTHRU;
-
   edge e = make_edge (region_copy[n_region - 1], exit->dest, EDGE_FALLTHRU);
 
   if (e) {