re PR tree-optimization/64193 (Decreased performance after r173250)

2014-12-09  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/64193
	* tree-ssa-alias.c (walk_non_aliased_vuses): Add valueize parameter
	and valueize the VUSE before looking up the def stmt.
	* tree-ssa-alias.h (walk_non_aliased_vuses): Adjust prototype.
	* tree-ssa-sccvn.c (vn_reference_lookup_pieces): Pass vn_valueize
	to walk_non_aliased_vuses.
	(vn_reference_lookup): Likewise.
	* tree-ssa-dom.c (lookup_avail_expr): Pass NULL as valueize
	callback to walk_non_aliased_vuses.

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

From-SVN: r218515

gcc/ChangeLog

@@ -1,3 +1,15 @@
+2014-12-09  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/64193
+	* tree-ssa-alias.c (walk_non_aliased_vuses): Add valueize parameter
+	and valueize the VUSE before looking up the def stmt.
+	* tree-ssa-alias.h (walk_non_aliased_vuses): Adjust prototype.
+	* tree-ssa-sccvn.c (vn_reference_lookup_pieces): Pass vn_valueize
+	to walk_non_aliased_vuses.
+	(vn_reference_lookup): Likewise.
+	* tree-ssa-dom.c (lookup_avail_expr): Pass NULL as valueize
+	callback to walk_non_aliased_vuses.
+
 2014-12-09  Richard Biener  <rguenther@suse.de>
 
 	PR middle-end/64199

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2014-12-09  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/64193
+	* gcc.dg/tree-ssa/ssa-fre-43.c: New testcase.
+
 2014-12-09  Richard Biener  <rguenther@suse.de>
 
 	PR middle-end/64199

gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-43.c

@@ -0,0 +1,29 @@
+/* PR tree-optimization/64193 */
+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-fre1-details" } */
+
+double T,T2,E1[5];
+int J;
+
+void
+PA(double E[])
+{
+ J = 0;
+
+L10:
+ E[1] = ( E[1] + E[2] + E[3] - E[4]) * T;
+ E[2] = ( E[1] + E[2] - E[3] + E[4]) * T;
+ E[3] = ( E[1] - E[2] + E[3] + E[4]) * T;
+ E[4] = (-E[1] + E[2] + E[3] + E[4]) / T2;
+ J += 1;
+
+ if (J < 6)
+  goto L10;
+}
+
+/* We should remove 15 dead loads, 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-not "Not changing value number" "fre1" } } */
+/* { dg-final { cleanup-tree-dump "fre1" } } */

gcc/tree-ssa-alias.c

@@ -2632,12 +2632,18 @@ get_continuation_for_phi (gimple phi, ao_ref *ref,
    If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
    to adjust REF and *DATA to make that valid.
 
+   VALUEIZE if non-NULL is called with the next VUSE that is considered
+   and return value is substituted for that.  This can be used to
+   implement optimistic value-numbering for example.  Note that the
+   VUSE argument is assumed to be valueized already.
+
    TODO: Cache the vector of equivalent vuses per ref, vuse pair.  */
 
 void *
 walk_non_aliased_vuses (ao_ref *ref, tree vuse,
 			void *(*walker)(ao_ref *, tree, unsigned int, void *),
 			void *(*translate)(ao_ref *, tree, void *, bool),
+			tree (*valueize)(tree),
 			void *data)
 {
   bitmap visited = NULL;
@@ -2663,6 +2669,8 @@ walk_non_aliased_vuses (ao_ref *ref, tree vuse,
       else if (res != NULL)
 	break;
 
+      if (valueize)
+	vuse = valueize (vuse);
       def_stmt = SSA_NAME_DEF_STMT (vuse);
       if (gimple_nop_p (def_stmt))
 	break;

gcc/tree-ssa-alias.h

@@ -124,6 +124,7 @@ extern void *walk_non_aliased_vuses (ao_ref *, tree,
 				     void *(*)(ao_ref *, tree,
 					       unsigned int, void *),
 				     void *(*)(ao_ref *, tree, void *, bool),
+				     tree (*)(tree),
 				     void *);
 extern unsigned int walk_aliased_vdefs (ao_ref *, tree,
 					bool (*)(ao_ref *, tree, void *),

gcc/tree-ssa-dom.c

@@ -2635,7 +2635,7 @@ lookup_avail_expr (gimple stmt, bool insert)
 	    && TREE_CODE (gimple_assign_lhs (stmt)) == SSA_NAME
 	    && (ao_ref_init (&ref, gimple_assign_rhs1 (stmt)), true)
 	    && walk_non_aliased_vuses (&ref, vuse2,
-				       vuse_eq, NULL, vuse1) != NULL))
+				       vuse_eq, NULL, NULL, vuse1) != NULL))
 	{
 	  struct expr_hash_elt *element2 = XNEW (struct expr_hash_elt);
 	  *element2 = element;

gcc/tree-ssa-sccvn.c

@@ -2160,7 +2160,8 @@ vn_reference_lookup_pieces (tree vuse, alias_set_type set, tree type,
 	*vnresult =
 	  (vn_reference_t)walk_non_aliased_vuses (&r, vr1.vuse,
 						  vn_reference_lookup_2,
-						  vn_reference_lookup_3, &vr1);
+						  vn_reference_lookup_3,
+						  vn_valueize, &vr1);
       gcc_checking_assert (vr1.operands == shared_lookup_references);
     }
 
@@ -2212,7 +2213,8 @@ vn_reference_lookup (tree op, tree vuse, vn_lookup_kind kind,
       wvnresult =
 	(vn_reference_t)walk_non_aliased_vuses (&r, vr1.vuse,
 						vn_reference_lookup_2,
-						vn_reference_lookup_3, &vr1);
+						vn_reference_lookup_3,
+						vn_valueize, &vr1);
       gcc_checking_assert (vr1.operands == shared_lookup_references);
       if (wvnresult)
 	{