drop halide2isl::findReductions

Now that all users of reductions have switched to the polyhedral
representation, the original representation can be removed.

Author: Sven Verdoolaege

tc/core/halide2isl.cc

@@ -572,60 +572,5 @@ ScheduleTreeAndAccesses makeScheduleTree(isl::space paramSpace, const Stmt& s) {
   return result;
 }
 
-std::vector<Reduction> findReductions(const Stmt& s) {
-  class FindReductions : public IRVisitor {
-    using IRVisitor::visit;
-
-    // Keep track of any reduction variable name for use in visit(Provide*)
-    void visit(const Variable* op) {
-      if (op->reduction_domain.defined()) {
-        reductionVars.insert(op->name);
-      }
-    }
-
-    // Keep track of the names of the outer For nodes.
-    void visit(const For* op) {
-      vars.push_back(op->name);
-      IRVisitor::visit(op);
-      vars.pop_back();
-    }
-
-    // Check if the node is an update node with at least one reduction
-    // dimension, keeping track of the information about the reduction.
-    // In particular, collect the positions of the reduction
-    // dimensions in the update statement domain.
-    // Visit the children first to ensure that all relevant
-    // reduction variables have been found first.
-    void visit(const Provide* op) {
-      IRVisitor::visit(op);
-      if (isReductionUpdate(op)) {
-        std::vector<size_t> dims;
-        auto n = vars.size();
-        for (size_t i = 0; i < n; ++i) {
-          if (reductionVars.count(vars[i]) != 0) {
-            dims.emplace_back(i);
-          }
-        }
-        if (dims.size() > 0) {
-          Reduction p;
-          p.update = op;
-          p.dims = dims;
-          reductions.emplace_back(p);
-        }
-      }
-    }
-
-   public:
-    // The variables that are known to be reduction variables.
-    std::unordered_set<std::string> reductionVars;
-    // The names of the outer For nodes, outermost to innermost.
-    std::vector<std::string> vars;
-    std::vector<Reduction> reductions;
-  } finder;
-  s.accept(&finder);
-
-  return finder.reductions;
-}
-
 } // namespace halide2isl
 } // namespace tc

tc/core/halide2isl.h

@@ -105,17 +105,5 @@ ScheduleTreeAndAccesses makeScheduleTree(
     isl::space paramSpace,
     const Halide::Internal::Stmt& s);
 
-/// Enumerate all reductions in a statement, by looking for the
-/// ReductionUpdate markers inserted during lowering
-/// (see tc2halide.h).
-/// Each reduction object stores a reference to
-/// the update statement, and a list of reduction dimensions
-/// in the domain of the update statement.
-struct Reduction {
-  Halide::Internal::Stmt update;
-  std::vector<size_t> dims;
-};
-std::vector<Reduction> findReductions(const Halide::Internal::Stmt& s);
-
 } // namespace halide2isl
 } // namespace tc

tc/core/polyhedral/scop.cc

@@ -64,7 +64,6 @@ ScopUPtr Scop::makeScop(
   scop->body = tree.body;
   scop->halide.statements = std::move(tree.statements);
   scop->halide.accesses = std::move(tree.accesses);
-  scop->halide.reductions = halide2isl::findReductions(components.stmt);
   scop->halide.domains = std::move(tree.domains);
 
   return scop;

tc/core/polyhedral/scop.h

@@ -485,7 +485,6 @@ struct Scop {
     std::vector<std::string> idx, reductionIdx;
     std::vector<Halide::ImageParam> inputs;
     std::vector<Halide::OutputImageParam> outputs;
-    std::vector<halide2isl::Reduction> reductions;
     std::unordered_map<isl::id, Halide::Internal::Stmt, isl::IslIdIslHash>
         statements;
     std::unordered_map<const Halide::Internal::IRNode*, isl::id> accesses;