[Mlir-commits] [mlir] Reland "[mlir][reducer] Add eraseRedundantBlocksInRegion and getSuccessorForwardOperands API to BranchOpInterface" (PR #189253)

[llvmlistbot at llvm.org]

google-yfyang wrote:

This change fails one tensorflow test https://github.com/tensorflow/tensorflow/blob/master/tensorflow/compiler/mlir/tensorflow/tests/tf-reduce-identity.mlir:

with the following error message:
```
F0406 14:13:41.672739   10333 logging.cc:51] assert.h assertion failed at [llvm-project/mlir/lib/Transforms/Utils/GreedyPatternRewriteDriver.cpp:919] in LogicalResult mlir::applyPatternsGreedily(Region &, const FrozenRewritePatternSet &, GreedyRewriteConfig, bool *): region.getParentOp()->hasTrait<OpTrait::IsIsolatedFromAbove>() && "patterns can only be applied to operations IsolatedFromAbove"
*** Check failure stack trace: ***
    @     0x5564180a0aa9  absl::log_internal::LogMessage::SendToLog()
    @     0x5564180a0a2e  absl::log_internal::LogMessage::Flush()
    @     0x5564180329f4  __assert_fail
    @     0x556415723eb1  mlir::applyPatternsGreedily()
    @     0x556414a23004  (anonymous namespace)::ReductionTreePass::runOnOperation()
    @     0x5564159782cc  llvm::function_ref<>::callback_fn<>()
    @     0x55641597030d  mlir::detail::OpToOpPassAdaptor::run()
    @     0x556415970e7e  mlir::detail::OpToOpPassAdaptor::runPipeline()
    @     0x556415976926  mlir::PassManager::runPasses()
    @     0x556415976127  mlir::PassManager::run()
    @     0x556414a1f099  mlir::mlirReduceMain()::$_1::operator()()
    @     0x556414a1e410  mlir::mlirReduceMain()
    @     0x55640f440321  main
    @     0x7fa363f53f12  __libc_start_main
    @     0x55640f44002a  _start
```

If I change 
```  
if (smallestNode == nullptr)
    (void)applyPatternsGreedily(region.getParentOp(), fPatterns, config);
```
to 
```
if (smallestNode == nullptr) {
      Operation *isolatedParent = region.getParentOp();
      if (!isolatedParent->hasTrait<OpTrait::IsIsolatedFromAbove>()) {
        isolatedParent =
            isolatedParent->getParentWithTrait<OpTrait::IsIsolatedFromAbove>();
      }

      if (isolatedParent) {
        (void)applyPatternsGreedily(isolatedParent, fPatterns, config);
      }
}
```
on line 294 in mlir/lib/Reducer/ReductionTreePass.cpp the test would pass. Does this solution look right to you?

https://github.com/llvm/llvm-project/pull/189253