re PR tree-optimization/91756 (g++.dg/lto/alias-3 FAILs)

2019-09-16  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/91756
	PR tree-optimization/87132
	* tree-ssa-alias.h (enum translate_flags): New.
	(get_continuation_for_phi): Use it instead of simple bool flag.
	(walk_non_aliased_vuses): Likewise.
	* tree-ssa-alias.c (maybe_skip_until): Adjust.
	(get_continuation_for_phi): When looking across backedges only
	disallow valueization.
	(walk_non_aliased_vuses): Adjust.
	* tree-ssa-sccvn.c (vn_reference_lookup_3): Avoid valueization
	if requested.

	* gcc.dg/tree-ssa/ssa-fre-81.c: New testcase.

From-SVN: r275747

6 files changed, 88 insertions, 22 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 41cf926..49b7902 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,17 @@
+2019-09-16  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/91756
+	PR tree-optimization/87132
+	* tree-ssa-alias.h (enum translate_flags): New.
+	(get_continuation_for_phi): Use it instead of simple bool flag.
+	(walk_non_aliased_vuses): Likewise.
+	* tree-ssa-alias.c (maybe_skip_until): Adjust.
+	(get_continuation_for_phi): When looking across backedges only
+	disallow valueization.
+	(walk_non_aliased_vuses): Adjust.
+	* tree-ssa-sccvn.c (vn_reference_lookup_3): Avoid valueization
+	if requested.
+
 2019-09-14  Kewen Lin  <linkw@gcc.gnu.org>
 
 	PR middle-end/80791
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 6a5ba09..b893ed0 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2019-09-16  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/91756
+	PR tree-optimization/87132
+	* gcc.dg/tree-ssa/ssa-fre-81.c: New testcase.
+
 2019-09-15  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/91740 - ICE with constexpr call and ?: in ARRAY_REF.
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-81.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-81.c
new file mode 100644
index 0000000..e88f666
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-81.c
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-fre1-details" } */
+
+struct a
+{
+  int foo,bar;
+};
+struct b
+{
+  struct a a[10];
+};
+struct b b, *bptr=&b, *bptr2=&b;
+int j;
+int i;
+int n=1;
+
+int
+main ()
+{
+  int jj=j;
+  bptr2->a[jj].bar = 0;
+  for (int i=0; i<n; i++)
+    bptr->a[i].foo=1;
+  if (!__builtin_constant_p (bptr2->a[jj].bar == 0))
+    __builtin_abort ();
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump "Replaced __builtin_constant_p \\\(\[^)\]*\\\) with 1" "fre1" } } */
diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index dd2a43e..52cda38 100644
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -3150,7 +3150,8 @@ static bool
 maybe_skip_until (gimple *phi, tree &target, basic_block target_bb,
 		  ao_ref *ref, tree vuse, bool tbaa_p, unsigned int &limit,
 		  bitmap *visited, bool abort_on_visited,
-		  void *(*translate)(ao_ref *, tree, void *, bool *),
+		  void *(*translate)(ao_ref *, tree, void *, translate_flags *),
+		  translate_flags disambiguate_only,
 		  void *data)
 {
   basic_block bb = gimple_bb (phi);
@@ -3185,7 +3186,7 @@ maybe_skip_until (gimple *phi, tree &target, basic_block target_bb,
 	    return !abort_on_visited;
 	  vuse = get_continuation_for_phi (def_stmt, ref, tbaa_p, limit,
 					   visited, abort_on_visited,
-					   translate, data);
+					   translate, data, disambiguate_only);
 	  if (!vuse)
 	    return false;
 	  continue;
@@ -3200,9 +3201,9 @@ maybe_skip_until (gimple *phi, tree &target, basic_block target_bb,
 	  --limit;
 	  if (stmt_may_clobber_ref_p_1 (def_stmt, ref, tbaa_p))
 	    {
-	      bool disambiguate_only = true;
+	      translate_flags tf = disambiguate_only;
 	      if (translate
-		  && (*translate) (ref, vuse, data, &disambiguate_only) == NULL)
+		  && (*translate) (ref, vuse, data, &tf) == NULL)
 		;
 	      else
 		return false;
@@ -3233,8 +3234,10 @@ tree
 get_continuation_for_phi (gimple *phi, ao_ref *ref, bool tbaa_p,
 			  unsigned int &limit, bitmap *visited,
 			  bool abort_on_visited,
-			  void *(*translate)(ao_ref *, tree, void *, bool *),
-			  void *data)
+			  void *(*translate)(ao_ref *, tree, void *,
+					     translate_flags *),
+			  void *data,
+			  translate_flags disambiguate_only)
 {
   unsigned nargs = gimple_phi_num_args (phi);
 
@@ -3276,13 +3279,15 @@ get_continuation_for_phi (gimple *phi, ao_ref *ref, bool tbaa_p,
       else if (! maybe_skip_until (phi, arg0, dom, ref, arg1, tbaa_p,
 				   limit, visited,
 				   abort_on_visited,
-				   /* Do not translate when walking over
+				   translate,
+				   /* Do not valueize when walking over
 				      backedges.  */
 				   dominated_by_p
 				     (CDI_DOMINATORS,
 				      gimple_bb (SSA_NAME_DEF_STMT (arg1)),
 				      phi_bb)
-				   ? NULL : translate, data))
+				   ? TR_DISAMBIGUATE
+				   : disambiguate_only, data))
 	return NULL_TREE;
     }
 
@@ -3320,7 +3325,8 @@ get_continuation_for_phi (gimple *phi, ao_ref *ref, bool tbaa_p,
 void *
 walk_non_aliased_vuses (ao_ref *ref, tree vuse, bool tbaa_p,
 			void *(*walker)(ao_ref *, tree, void *),
-			void *(*translate)(ao_ref *, tree, void *, bool *),
+			void *(*translate)(ao_ref *, tree, void *,
+					   translate_flags *),
 			tree (*valueize)(tree),
 			unsigned &limit, void *data)
 {
@@ -3373,7 +3379,7 @@ walk_non_aliased_vuses (ao_ref *ref, tree vuse, bool tbaa_p,
 	    {
 	      if (!translate)
 		break;
-	      bool disambiguate_only = false;
+	      translate_flags disambiguate_only = TR_TRANSLATE;
 	      res = (*translate) (ref, vuse, data, &disambiguate_only);
 	      /* Failed lookup and translation.  */
 	      if (res == (void *)-1)
@@ -3385,7 +3391,7 @@ walk_non_aliased_vuses (ao_ref *ref, tree vuse, bool tbaa_p,
 	      else if (res != NULL)
 		break;
 	      /* Translation succeeded, continue walking.  */
-	      translated = translated || !disambiguate_only;
+	      translated = translated || disambiguate_only == TR_TRANSLATE;
 	    }
 	  vuse = gimple_vuse (def_stmt);
 	}
diff --git a/gcc/tree-ssa-alias.h b/gcc/tree-ssa-alias.h
index c7c6020..6d72c2f 100644
--- a/gcc/tree-ssa-alias.h
+++ b/gcc/tree-ssa-alias.h
@@ -132,13 +132,18 @@ extern bool call_may_clobber_ref_p (gcall *, tree);
 extern bool call_may_clobber_ref_p_1 (gcall *, ao_ref *);
 extern bool stmt_kills_ref_p (gimple *, tree);
 extern bool stmt_kills_ref_p (gimple *, ao_ref *);
+enum translate_flags
+  { TR_TRANSLATE, TR_VALUEIZE_AND_DISAMBIGUATE, TR_DISAMBIGUATE };
 extern tree get_continuation_for_phi (gimple *, ao_ref *, bool,
 				      unsigned int &, bitmap *, bool,
-				      void *(*)(ao_ref *, tree, void *, bool *),
-				      void *);
+				      void *(*)(ao_ref *, tree, void *,
+						translate_flags *),
+				      void *, translate_flags
+				        = TR_VALUEIZE_AND_DISAMBIGUATE);
 extern void *walk_non_aliased_vuses (ao_ref *, tree, bool,
 				     void *(*)(ao_ref *, tree, void *),
-				     void *(*)(ao_ref *, tree, void *, bool *),
+				     void *(*)(ao_ref *, tree, void *,
+					       translate_flags *),
 				     tree (*)(tree), unsigned &, void *);
 extern int walk_aliased_vdefs (ao_ref *, tree,
 			       bool (*)(ao_ref *, tree, void *),
diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c
index f5d75bd..c29e2de 100644
--- a/gcc/tree-ssa-sccvn.c
+++ b/gcc/tree-ssa-sccvn.c
@@ -2189,7 +2189,7 @@ adjust_offsets_for_equal_base_address (tree base1, poly_int64 *offset1,
 
 static void *
 vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_,
-		       bool *disambiguate_only)
+		       translate_flags *disambiguate_only)
 {
   vn_walk_cb_data *data = (vn_walk_cb_data *)data_;
   vn_reference_t vr = data->vr;
@@ -2210,8 +2210,11 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_,
       lhs_ops.truncate (0);
       basic_block saved_rpo_bb = vn_context_bb;
       vn_context_bb = gimple_bb (def_stmt);
-      copy_reference_ops_from_ref (lhs, &lhs_ops);
-      lhs_ops = valueize_refs_1 (lhs_ops, &valueized_anything, true);
+      if (*disambiguate_only <= TR_VALUEIZE_AND_DISAMBIGUATE)
+	{
+	  copy_reference_ops_from_ref (lhs, &lhs_ops);
+	  lhs_ops = valueize_refs_1 (lhs_ops, &valueized_anything, true);
+	}
       vn_context_bb = saved_rpo_bb;
       if (valueized_anything)
 	{
@@ -2221,7 +2224,7 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_,
 	  if (lhs_ref_ok
 	      && !refs_may_alias_p_1 (ref, &lhs_ref, data->tbaa_p))
 	    {
-	      *disambiguate_only = true;
+	      *disambiguate_only = TR_VALUEIZE_AND_DISAMBIGUATE;
 	      return NULL;
 	    }
 	}
@@ -2248,7 +2251,9 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_,
 	    }
 	  if (!refs_may_alias_p_1 (&data->orig_ref, lref, data->tbaa_p))
 	    {
-	      *disambiguate_only = true;
+	      *disambiguate_only = (valueized_anything
+				    ? TR_VALUEIZE_AND_DISAMBIGUATE
+				    : TR_DISAMBIGUATE);
 	      return NULL;
 	    }
 	}
@@ -2290,7 +2295,8 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_,
 	    }
 	}
     }
-  else if (gimple_call_builtin_p (def_stmt, BUILT_IN_NORMAL)
+  else if (*disambiguate_only <= TR_VALUEIZE_AND_DISAMBIGUATE
+	   && gimple_call_builtin_p (def_stmt, BUILT_IN_NORMAL)
 	   && gimple_call_num_args (def_stmt) <= 4)
     {
       /* For builtin calls valueize its arguments and call the
@@ -2319,7 +2325,7 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_,
 	    gimple_call_set_arg (def_stmt, i, oldargs[i]);
 	  if (!res)
 	    {
-	      *disambiguate_only = true;
+	      *disambiguate_only = TR_VALUEIZE_AND_DISAMBIGUATE;
 	      return NULL;
 	    }
 	}
@@ -2327,7 +2333,7 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_,
 
   /* If we are looking for redundant stores do not create new hashtable
      entries from aliasing defs with made up alias-sets.  */
-  if (*disambiguate_only || !data->tbaa_p)
+  if (*disambiguate_only > TR_TRANSLATE || !data->tbaa_p)
     return (void *)-1;
 
   /* If we cannot constrain the size of the reference we cannot