Add support for processing Ops with empty region to the CSE

[Ding]

Summary

Automated commit created by applying diff 491559

Phabricator-ID: PHID-HMBT-wntxrq6q44z2nhnbj4wz
Review-ID: D141900

[Ding]

Updating D143839: Add support for processing Ops with empty region to the CSE

mlir/lib/Transforms/CSE.cpp

 
 namespace mlir {
 #define GEN_PASS_DEF_CSE
 #include "mlir/Transforms/Passes.h.inc"
 } // namespace mlir
 
 using namespace mlir;
 
+static bool hasNoOrEmptyRegions(Operation *op) {
+  return op->getNumRegions() == 0 ||
+         llvm::all_of(op->getRegions(),
+                      [](auto &region) { return region.empty(); });
+}
+
+static bool hasSingleRegionWithSingleBlock(Operation *op) {
+  return op->getNumRegions() == 1 && llvm::hasSingleElement(op->getRegion(0));
+}
+
 namespace {
 struct SimpleOperationInfo : public llvm::DenseMapInfo<Operation *> {
   static unsigned getHashValue(const Operation *opC) {
     return OperationEquivalence::computeHash(
         const_cast<Operation *>(opC),
         /*hashOperands=*/OperationEquivalence::directHashValue,
         /*hashResults=*/OperationEquivalence::ignoreHashValue,
         OperationEquivalence::IgnoreLocations);

mlir/test/Transforms/cse.mlir

 //       CHECK:   %[[if:.*]] = scf.if {{.*}} {
 //       CHECK:     tensor.empty
 //       CHECK:     scf.yield
 //       CHECK:   } else {
 //       CHECK:     scf.yield
 //       CHECK:   }
 //   CHECK-NOT:   scf.if
 //       CHECK:   return %[[if]], %[[if]]
+
+// Operations with empty region CSE
+// CHECK-LABEL: func @cse_ops_with_empty_region
+//       CHECK:   %[[OP0:.*[0]]] = "test.any_cond"
+//   CHECK-NOT:   %[[OP1:.*[0]]] = "test.any_cond"
+//        CHECK:   return %[[OP0]], %[[OP0]]
+func.func @cse_ops_with_empty_region()
+  -> (i32, i32) {
+  %0 = "test.any_cond"() ({
+  }) : () -> i32
+  %1 = "test.any_cond"() ({
+  }) : () -> i32
+  return %0, %1 : i32, i32
+}