re PR tree-optimization/61034 (Optimizing takes too many passes)

2014-05-07  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/61034
	* tree-ssa-alias.c (call_may_clobber_ref_p_1): Export.
	(maybe_skip_until): Use translate to take into account
	lattices when trying to do disambiguations.
	(get_continuation_for_phi_1): Likewise.
	(get_continuation_for_phi): Adjust for added translate
	arguments.
	(walk_non_aliased_vuses): Likewise.
	* tree-ssa-alias.h (get_continuation_for_phi): Adjust
	prototype.
	(walk_non_aliased_vuses): Likewise.
	(call_may_clobber_ref_p_1): Declare.
	* tree-ssa-sccvn.c (vn_reference_lookup_3): Also
	disambiguate against calls.  Stop early if we are
	only supposed to disambiguate.
	* tree-ssa-pre.c (translate_vuse_through_block): Adjust.

	* g++.dg/tree-ssa/pr61034.C: New testcase.

From-SVN: r210160

1 files changed, 35 insertions, 1 deletions

diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c
index 585fd85..05a5fe8 100644
--- a/gcc/tree-ssa-sccvn.c
+++ b/gcc/tree-ssa-sccvn.c
@@ -1542,7 +1542,8 @@ vn_reference_lookup_or_insert_for_pieces (tree vuse,
    of VUSE.  */
 
 static void *
-vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *vr_)
+vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *vr_,
+		       bool disambiguate_only)
 {
   vn_reference_t vr = (vn_reference_t)vr_;
   gimple def_stmt = SSA_NAME_DEF_STMT (vuse);
@@ -1580,6 +1581,39 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *vr_)
 	  lhs_ref_ok = true;
 	}
     }
+  else if (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
+         alias oracle again.  Valueization may improve points-to
+	 info of pointers and constify size and position arguments.
+	 Originally this was motivated by PR61034 which has
+	 conditional calls to free falsely clobbering ref because
+	 of imprecise points-to info of the argument.  */
+      tree oldargs[4];
+      bool valueized_anything;
+      for (unsigned i = 0; i < gimple_call_num_args (def_stmt); ++i)
+	{
+	  oldargs[i] = gimple_call_arg (def_stmt, i);
+	  if (TREE_CODE (oldargs[i]) == SSA_NAME
+	      && VN_INFO (oldargs[i])->valnum != oldargs[i])
+	    {
+	      gimple_call_set_arg (def_stmt, i, VN_INFO (oldargs[i])->valnum);
+	      valueized_anything = true;
+	    }
+	}
+      if (valueized_anything)
+	{
+	  bool res = call_may_clobber_ref_p_1 (def_stmt, ref);
+	  for (unsigned i = 0; i < gimple_call_num_args (def_stmt); ++i)
+	    gimple_call_set_arg (def_stmt, i, oldargs[i]);
+	  if (!res)
+	    return NULL;
+	}
+    }
+
+  if (disambiguate_only)
+    return (void *)-1;
 
   base = ao_ref_base (ref);
   offset = ref->offset;