isReductionUpdateId: stop returning corresponding init statement

Since the previous commit, this information is no longer needed.

Author: Sven Verdoolaege

tc/core/polyhedral/reduction_matcher.cc

@@ -48,12 +48,10 @@ bool isSupportedReduction(Halide::Internal::Stmt stmt) {
 // the reduction.  that is a kind of internal state dependence we want to avoid
 // If id is the statement identifier of an update statement
 // of a supported type of reduction,
-// then return the corresponding init statement in init and
-// the corresponding reduction dimensions in reductionDims.
+// then return the corresponding reduction dimensions in reductionDims.
 bool isReductionUpdateId(
     isl::id id,
     const Scop& scop,
-    Halide::Internal::Stmt& init,
     std::vector<size_t>& reductionDims) {
   CHECK_EQ(scop.halide.statements.count(id), 1u)
       << "id is not a statement in scop" << id;
@@ -63,7 +61,6 @@ bool isReductionUpdateId(
   }
   for (auto const& iup : scop.halide.reductions) {
     if (iup.update.same_as(provideNode)) {
-      init = iup.init;
       reductionDims = iup.dims;
       return true;
     }
@@ -104,9 +101,8 @@ bool isAlmostIdentityReduction(isl::pw_aff pa, const Scop& scop) {
     return false;
   }
   auto stmtId = space.get_tuple_id(isl::dim_type::in);
-  Halide::Internal::Stmt init;
   std::vector<size_t> reductionDims;
-  if (!isReductionUpdateId(stmtId, scop, init, reductionDims)) {
+  if (!isReductionUpdateId(stmtId, scop, reductionDims)) {
     return false;
   }
 
@@ -124,9 +120,8 @@ isl::union_set reductionUpdates(isl::union_set domain, const Scop& scop) {
   auto update = isl::union_set::empty(domain.get_space());
   domain.foreach_set([&update, &scop](isl::set set) {
     auto setId = set.get_tuple_id();
-    Halide::Internal::Stmt initStmt;
     std::vector<size_t> reductionDims;
-    if (isReductionUpdateId(setId, scop, initStmt, reductionDims)) {
+    if (isReductionUpdateId(setId, scop, reductionDims)) {
       update = update.unite(set);
     }
   });