[CALCITE-6718] Optimize SubstitutionVisitor's splitFilter with early return and uniform simplification for equivalence checking

Author: wangyanjing

core/src/main/java/org/apache/calcite/plan/SubstitutionVisitor.java

@@ -297,8 +297,11 @@ void register(MutableRel result, MutableRel query) {
       RexNode condition, RexNode target) {
     final RexBuilder rexBuilder = simplify.rexBuilder;
     condition = simplify.simplify(condition);
-    target = simplify.simplify(target);
     RexNode condition2 = canonizeNode(rexBuilder, condition);
+    if (target.isAlwaysTrue()) {
+      return condition2;
+    }
+    target = simplify.simplify(target);
     RexNode target2 = canonizeNode(rexBuilder, target);
 
     // First, try splitting into ORs.
@@ -322,7 +325,9 @@ void register(MutableRel result, MutableRel query) {
               ImmutableList.of(condition2, target2));
       RexNode r =
           canonizeNode(rexBuilder, simplify.simplifyUnknownAsFalse(x2));
-      if (!r.isAlwaysFalse() && isEquivalent(condition2, r)) {
+      RexNode simplifiedCond2 =
+          canonizeNode(rexBuilder, simplify.simplifyUnknownAsFalse(condition2));
+      if (!r.isAlwaysFalse() && isEquivalent(simplifiedCond2, r)) {
         List<RexNode> conjs = RelOptUtil.conjunctions(r);
         for (RexNode e : RelOptUtil.conjunctions(target2)) {
           removeAll(conjs, e);