Dialect conversion crash: unlinked block

[bondhugula]

This should be reproducible with the trunk: f33f6e16ec430da0989d5e3a287bed1d6d55f73f. More inspection shows that we have a block with a null parent region. (This was likely exposed from the folding being done during dialect conversion.) Although -convert-linalg-to-llvm will go away, there is likely an underlying issue.

func @crash(%arg0: memref<256x256xf32>, %arg1: memref<256x256xf32>, %arg2: memref<256x256xf32>) {
  affine.for %arg3 = 0 to 2 {
    affine.for %arg4 = 0 to 4 {
      affine.for %arg5 = (d0) -> (d0 * 32)(%arg3) to (d0) -> (d0 * 32 + 32)(%arg3) {
      }
    }
  }
  return 
}

$ mlir-opt -debug  -convert-linalg-to-llvm   /tmp/crash.mlir 
Args: ../../llvm-project-bondhugula/build/bin/mlir-opt -debug -convert-linalg-to-llvm /tmp/crash.mlir 
    discovered a new reachable node ^bb0
    discovered a new reachable node ^bb0
    discovered a new reachable node ^bb0
    discovered a new reachable node ^bb0
    discovered a new reachable node ^bb0
Legalizing operation : module
-- Success : Operation marked legal by the target
Legalizing operation : func
-* Applying rewrite pattern 'func -> ()'.
** Inserting operation : llvm.func
** Inserting operation : llvm.load
** Inserting operation : llvm.load
** Inserting operation : llvm.load
** Erasing operation : func
Legalizing operation : llvm.func
-- Success : Operation marked legal by the target
Legalizing operation : llvm.load
-- Success : Operation marked legal by the target
Legalizing operation : llvm.load
-- Success : Operation marked legal by the target
Legalizing operation : llvm.load
-- Success : Operation marked legal by the target
Legalizing operation : affine.for
-* Applying rewrite pattern 'affine.for -> ()'.
** Inserting operation : std.constant
** Inserting operation : std.constant
** Inserting operation : std.constant
** Inserting operation : loop.for
** Erasing operation : affine.for
Legalizing operation : std.constant
-* Applying rewrite pattern 'std.constant -> ()'.
** Inserting operation : llvm.mlir.constant
** Replacing operation : std.constant
Legalizing operation : llvm.mlir.constant
-- Success : Operation marked legal by the target
Legalizing operation : std.constant
-* Applying rewrite pattern 'std.constant -> ()'.
** Inserting operation : llvm.mlir.constant
** Replacing operation : std.constant
Legalizing operation : llvm.mlir.constant
-- Success : Operation marked legal by the target
Legalizing operation : std.constant
-* Applying rewrite pattern 'std.constant -> ()'.
** Inserting operation : llvm.mlir.constant
** Replacing operation : std.constant
Legalizing operation : llvm.mlir.constant
-- Success : Operation marked legal by the target
Legalizing operation : loop.for
-* Applying rewrite pattern 'loop.for -> ()'.
** Inserting operation : std.addi
** Inserting operation : std.br
** Inserting operation : std.br
** Inserting operation : std.cmpi
** Inserting operation : std.cond_br
** Erasing operation : loop.for
Legalizing operation : std.addi
-* Applying rewrite pattern 'std.addi -> ()'.
** Inserting operation : llvm.add
** Replacing operation : std.addi
Legalizing operation : llvm.add
-- Success : Operation marked legal by the target
Legalizing operation : std.br
-* Applying rewrite pattern 'std.br -> ()'.
** Inserting operation : llvm.br
** Replacing operation : std.br
Legalizing operation : llvm.br
-- Success : Operation marked legal by the target
Legalizing operation : std.br
-* Applying rewrite pattern 'std.br -> ()'.
** Inserting operation : llvm.br
** Replacing operation : std.br
Legalizing operation : llvm.br
-- Success : Operation marked legal by the target
Legalizing operation : std.cmpi
-* Applying rewrite pattern 'std.cmpi -> ()'.
** Inserting operation : llvm.icmp
** Replacing operation : std.cmpi
Legalizing operation : llvm.icmp
-- Success : Operation marked legal by the target
Legalizing operation : std.cond_br
-* Applying rewrite pattern 'std.cond_br -> ()'.
** Inserting operation : llvm.cond_br
** Replacing operation : std.cond_br
Legalizing operation : llvm.cond_br
-- Success : Operation marked legal by the target
Legalizing operation : affine.for
-* Applying rewrite pattern 'affine.for -> ()'.
** Inserting operation : std.constant
** Inserting operation : std.constant
** Inserting operation : std.constant
** Inserting operation : loop.for
** Erasing operation : affine.for
Legalizing operation : std.constant
-* Applying rewrite pattern 'std.constant -> ()'.
** Inserting operation : llvm.mlir.constant
** Replacing operation : std.constant
Legalizing operation : llvm.mlir.constant
-- Success : Operation marked legal by the target
Legalizing operation : std.constant
-* Applying rewrite pattern 'std.constant -> ()'.
** Inserting operation : llvm.mlir.constant
** Replacing operation : std.constant
Legalizing operation : llvm.mlir.constant
-- Success : Operation marked legal by the target
Legalizing operation : std.constant
-* Applying rewrite pattern 'std.constant -> ()'.
** Inserting operation : llvm.mlir.constant
** Replacing operation : std.constant
Legalizing operation : llvm.mlir.constant
-- Success : Operation marked legal by the target
Legalizing operation : loop.for
-* Applying rewrite pattern 'loop.for -> ()'.
** Inserting operation : std.addi
** Inserting operation : std.br
** Inserting operation : std.br
** Inserting operation : std.cmpi
** Inserting operation : std.cond_br
** Erasing operation : loop.for
Legalizing operation : std.addi
-* Applying rewrite pattern 'std.addi -> ()'.
** Inserting operation : llvm.add
** Replacing operation : std.addi
Legalizing operation : llvm.add
-- Success : Operation marked legal by the target
Legalizing operation : std.br
-* Applying rewrite pattern 'std.br -> ()'.
** Inserting operation : llvm.br
** Replacing operation : std.br
Legalizing operation : llvm.br
-- Success : Operation marked legal by the target
Legalizing operation : std.br
-* Applying rewrite pattern 'std.br -> ()'.
** Inserting operation : llvm.br
** Replacing operation : std.br
Legalizing operation : llvm.br
-- Success : Operation marked legal by the target
Legalizing operation : std.cmpi
-* Applying rewrite pattern 'std.cmpi -> ()'.
** Inserting operation : llvm.icmp
** Replacing operation : std.cmpi
Legalizing operation : llvm.icmp
-- Success : Operation marked legal by the target
Legalizing operation : std.cond_br
-* Applying rewrite pattern 'std.cond_br -> ()'.
** Inserting operation : llvm.cond_br
** Replacing operation : std.cond_br
Legalizing operation : llvm.cond_br
-- Success : Operation marked legal by the target
Legalizing operation : affine.for
Stack dump:
0.  Program arguments: ../../llvm-project-bondhugula/build/bin/mlir-opt -debug -convert-linalg-to-llvm /tmp/crash.mlir 
 #0 0x0000000000d9f609 llvm::sys::PrintStackTrace(llvm::raw_ostream&) /home/uday/llvm-project-bondhugula/llvm/lib/Support/Unix/Signals.inc:548:11
 #1 0x0000000000d9f7b9 PrintStackTraceSignalHandler(void*) /home/uday/llvm-project-bondhugula/llvm/lib/Support/Unix/Signals.inc:609:1
 #2 0x0000000000d9e016 llvm::sys::RunSignalHandlers() /home/uday/llvm-project-bondhugula/llvm/lib/Support/Signals.cpp:67:5
 #3 0x0000000000d9ff4b SignalHandler(int) /home/uday/llvm-project-bondhugula/llvm/lib/Support/Unix/Signals.inc:390:1
 #4 0x00007fd4e19ccc70 __restore_rt (/lib64/libpthread.so.0+0x12c70)
 #5 0x0000000000cc642c mlir::Region::getParentOp() /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/IR/Region.cpp:50:43
 #6 0x00000000004d3cc5 isFunctionRegion(mlir::Region*) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/Dialect/AffineOps/AffineOps.cpp:112:28
 #7 0x00000000004d3c6d mlir::isTopLevelValue(mlir::Value*) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/Dialect/AffineOps/AffineOps.cpp:120:5
 #8 0x00000000004d3f62 mlir::isValidSymbol(mlir::Value*) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/Dialect/AffineOps/AffineOps.cpp:203:3
 #9 0x00000000004e5572 void canonicalizePromotedSymbols<mlir::AffineMap>(mlir::AffineMap*, llvm::SmallVectorImpl<mlir::Value*>*) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/Dialect/AffineOps/AffineOps.cpp:639:11
#10 0x00000000004d6639 void canonicalizeMapOrSetAndOperands<mlir::AffineMap>(mlir::AffineMap*, llvm::SmallVectorImpl<mlir::Value*>*) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/Dialect/AffineOps/AffineOps.cpp:679:33
#11 0x00000000004d655d mlir::canonicalizeMapAndOperands(mlir::AffineMap*, llvm::SmallVectorImpl<mlir::Value*>*) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/Dialect/AffineOps/AffineOps.cpp:744:1
#12 0x00000000004dac63 canonicalizeLoopBounds(mlir::AffineForOp) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/Dialect/AffineOps/AffineOps.cpp:1411:38
#13 0x00000000004daaa4 mlir::AffineForOp::fold(llvm::ArrayRef<mlir::Attribute>, llvm::SmallVectorImpl<mlir::OpFoldResult>&) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/Dialect/AffineOps/AffineOps.cpp:1448:23
#14 0x00000000004f845a mlir::FoldingHook<mlir::AffineForOp, false, void>::foldHook(mlir::Operation*, llvm::ArrayRef<mlir::Attribute>, llvm::SmallVectorImpl<mlir::OpFoldResult>&) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/include/mlir/IR/OpDefinition.h:276:35
#15 0x0000000000cb7037 mlir::Operation::fold(llvm::ArrayRef<mlir::Attribute>, llvm::SmallVectorImpl<mlir::OpFoldResult>&) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/IR/Operation.cpp:646:31
#16 0x0000000000c6bb31 mlir::OpBuilder::tryFold(mlir::Operation*, llvm::SmallVectorImpl<mlir::Value*>&) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/IR/Builders.cpp:366:18
#17 0x0000000000a11a30 (anonymous namespace)::OperationLegalizer::legalizeWithFold(mlir::Operation*, mlir::ConversionPatternRewriter&) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/Transforms/DialectConversion.cpp:1042:23
#18 0x0000000000a1154a (anonymous namespace)::OperationLegalizer::legalize(mlir::Operation*, mlir::ConversionPatternRewriter&) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/Transforms/DialectConversion.cpp:1012:17
#19 0x0000000000a110e3 (anonymous namespace)::OperationConverter::convert(mlir::ConversionPatternRewriter&, mlir::Operation*) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/Transforms/DialectConversion.cpp:1346:26
#20 0x0000000000a0c75b (anonymous namespace)::OperationConverter::convertOperations(llvm::ArrayRef<mlir::Operation*>, mlir::TypeConverter*) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/Transforms/DialectConversion.cpp:1393:16
#21 0x0000000000a0c924 mlir::applyFullConversion(llvm::ArrayRef<mlir::Operation*>, mlir::ConversionTarget&, mlir::OwningRewritePatternList const&, mlir::TypeConverter*) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/Transforms/DialectConversion.cpp:1702:22
#22 0x0000000000a0c982 mlir::applyFullConversion(mlir::Operation*, mlir::ConversionTarget&, mlir::OwningRewritePatternList const&, mlir::TypeConverter*) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/Transforms/DialectConversion.cpp:1708:10
#23 0x0000000000529d95 (anonymous namespace)::ConvertLinalgToLLVMPass::runOnModule() /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/Conversion/LinalgToLLVM/LinalgToLLVM.cpp:547:14
#24 0x0000000000529bd6 mlir::ModulePass<(anonymous namespace)::ConvertLinalgToLLVMPass>::runOnOperation() /home/uday/llvm-project-bondhugula/llvm/projects/mlir/include/mlir/Pass/Pass.h:323:48
#25 0x0000000000733e7d mlir::Pass::run(mlir::Operation*, mlir::AnalysisManager) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/Pass/Pass.cpp:75:3
#26 0x0000000000734b97 mlir::OpPassManager::run(mlir::Operation*, mlir::AnalysisManager) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/Pass/Pass.cpp:228:22
#27 0x0000000000736361 mlir::PassManager::run(mlir::ModuleOp) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/Pass/Pass.cpp:582:28
#28 0x00000000006f3336 performActions(llvm::raw_ostream&, bool, bool, llvm::SourceMgr&, mlir::MLIRContext*, mlir::PassPipelineCLParser const&) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/Support/MlirOptMain.cpp:66:17
#29 0x00000000006f3190 processBuffer(llvm::raw_ostream&, std::unique_ptr<llvm::MemoryBuffer, std::default_delete<llvm::MemoryBuffer> >, bool, bool, mlir::PassPipelineCLParser const&) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/Support/MlirOptMain.cpp:91:12
#30 0x00000000006f305d mlir::MlirOptMain(llvm::raw_ostream&, std::unique_ptr<llvm::MemoryBuffer, std::default_delete<llvm::MemoryBuffer> >, mlir::PassPipelineCLParser const&, bool, bool, bool) /home/uday/llvm-project-bondhugula/llvm/projects/mlir/lib/Support/MlirOptMain.cpp:124:10
#31 0x0000000000c155de main /home/uday/llvm-project-bondhugula/llvm/projects/mlir/tools/mlir-opt/mlir-opt.cpp:83:17
#32 0x00007fd4e1462f43 __libc_start_main (/lib64/libc.so.6+0x23f43)
#33 0x00000000004116ce _start (../../llvm-project-bondhugula/build/bin/mlir-opt+0x4116ce)
Segmentation fault (core dumped)