<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/130019>130019</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [MLIR] `scf-forall-to-parallel` pass triggers Segmentation fault.
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            mlir
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          RiRi114
      </td>
    </tr>
</table>

<pre>
    Test on commit: 0f9720a6

steps to reproduce：
`mlir-opt  temp.mlir  -pass-pipeline='builtin.module(func.func(scf-forall-to-parallel))'  `

test case:
```mlir
module {
    func.func @process_elements(%range_x: index, %range_y: index) {
        scf.forall (%x, %y) in (%range_x, %range_y) {
            llvm.return
        }
        return
    }
}
```

crash trace:
```
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.      Program arguments: /home/fuzzing/llvm-project/build/bin/mlir-opt temp.mlir -pass-pipeline=builtin.module(func.func(scf-forall-to-parallel))
1.      MLIR Parser: custom op parser 'builtin.module'
2.      MLIR Parser: custom op parser 'func.func'
3.      MLIR Parser: custom op parser 'scf.forall'
 #0 0x000000000113ce77 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/fuzzing/llvm-project/build/bin/mlir-opt+0x113ce77)
 #1 0x000000000113aa0e llvm::sys::RunSignalHandlers() (/home/fuzzing/llvm-project/build/bin/mlir-opt+0x113aa0e)
 #2 0x000000000113d855 SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
 #3 0x00007b2d50421520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x0000000003046fc7 mlir::scf::ForallOp::ensureTerminator(mlir::Region&, mlir::OpBuilder&, mlir::Location) (/home/fuzzing/llvm-project/build/bin/mlir-opt+0x3046fc7)
 #5 0x0000000003046d37 mlir::scf::ForallOp::parse(mlir::OpAsmParser&, mlir::OperationState&) (/home/fuzzing/llvm-project/build/bin/mlir-opt+0x3046d37)
 #6 0x00000000069b881e (anonymous namespace)::OperationParser::parseOperation() Parser.cpp:0:0
 #7 0x00000000069c3d01 (anonymous namespace)::OperationParser::parseBlock(mlir::Block*&) Parser.cpp:0:0
 #8 0x00000000069c1b2a (anonymous namespace)::OperationParser::parseRegion(mlir::Region&, llvm::ArrayRef<mlir::OpAsmParser::Argument>, bool) Parser.cpp:0:0
 #9 0x00000000069bfbf9 (anonymous namespace)::CustomOpAsmParser::parseRegion(mlir::Region&, llvm::ArrayRef<mlir::OpAsmParser::Argument>, bool) Parser.cpp:0:0
#10 0x00000000069bfc3c (anonymous namespace)::CustomOpAsmParser::parseOptionalRegion(mlir::Region&, llvm::ArrayRef<mlir::OpAsmParser::Argument>, bool) Parser.cpp:0:0
#11 0x0000000006ac872b mlir::function_interface_impl::parseFunctionOp(mlir::OpAsmParser&, mlir::OperationState&, bool, mlir::StringAttr, llvm::function_ref<mlir::Type (mlir::Builder&, llvm::ArrayRef<mlir::Type>, llvm::ArrayRef<mlir::Type>, mlir::function_interface_impl::VariadicFlag, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&)>, mlir::StringAttr, mlir::StringAttr) (/home/fuzzing/llvm-project/build/bin/mlir-opt+0x6ac872b)
#12 0x00000000017e4928 mlir::func::FuncOp::parse(mlir::OpAsmParser&, mlir::OperationState&) (/home/fuzzing/llvm-project/build/bin/mlir-opt+0x17e4928)
#13 0x00000000069b881e (anonymous namespace)::OperationParser::parseOperation() Parser.cpp:0:0
#14 0x00000000069c3d01 (anonymous namespace)::OperationParser::parseBlock(mlir::Block*&) Parser.cpp:0:0
#15 0x00000000069c198e (anonymous namespace)::OperationParser::parseRegion(mlir::Region&, llvm::ArrayRef<mlir::OpAsmParser::Argument>, bool) Parser.cpp:0:0
#16 0x00000000069bfbf9 (anonymous namespace)::CustomOpAsmParser::parseRegion(mlir::Region&, llvm::ArrayRef<mlir::OpAsmParser::Argument>, bool) Parser.cpp:0:0
#17 0x00000000043648ce mlir::ModuleOp::parse(mlir::OpAsmParser&, mlir::OperationState&) (/home/fuzzing/llvm-project/build/bin/mlir-opt+0x43648ce)
#18 0x00000000069b881e (anonymous namespace)::OperationParser::parseOperation() Parser.cpp:0:0
#19 0x00000000069b7108 mlir::parseAsmSourceFile(llvm::SourceMgr const&, mlir::Block*, mlir::ParserConfig const&, mlir::AsmParserState*, mlir::AsmParserCodeCompleteContext*) (/home/fuzzing/llvm-project/build/bin/mlir-opt+0x69b7108)
#20 0x000000000424207f mlir::parseSourceFile(std::shared_ptr<llvm::SourceMgr> const&, mlir::Block*, mlir::ParserConfig const&, mlir::LocationAttr*) (/home/fuzzing/llvm-project/build/bin/mlir-opt+0x424207f)
#21 0x0000000004240f8e mlir::parseSourceFileForTool(std::shared_ptr<llvm::SourceMgr> const&, mlir::ParserConfig const&, bool) (/home/fuzzing/llvm-project/build/bin/mlir-opt+0x4240f8e)
#22 0x0000000004240793 performActions(llvm::raw_ostream&, std::shared_ptr<llvm::SourceMgr> const&, mlir::MLIRContext*, mlir::MlirOptMainConfig const&) MlirOptMain.cpp:0:0
#23 0x0000000004240503 llvm::LogicalResult llvm::function_ref<llvm::LogicalResult (std::unique_ptr<llvm::MemoryBuffer, std::default_delete<llvm::MemoryBuffer> >, llvm::raw_ostream&)>::callback_fn<mlir::MlirOptMain(llvm::raw_ostream&, std::unique_ptr<llvm::MemoryBuffer, std::default_delete<llvm::MemoryBuffer> >, mlir::DialectRegistry&, mlir::MlirOptMainConfig const&)::$_3>(long, std::unique_ptr<llvm::MemoryBuffer, std::default_delete<llvm::MemoryBuffer> >, llvm::raw_ostream&) MlirOptMain.cpp:0:0
#24 0x00000000042ec4e8 mlir::splitAndProcessBuffer(std::unique_ptr<llvm::MemoryBuffer, std::default_delete<llvm::MemoryBuffer> >, llvm::function_ref<llvm::LogicalResult (std::unique_ptr<llvm::MemoryBuffer, std::default_delete<llvm::MemoryBuffer> >, llvm::raw_ostream&)>, llvm::raw_ostream&, llvm::StringRef, llvm::StringRef) (/home/fuzzing/llvm-project/build/bin/mlir-opt+0x42ec4e8)
#25 0x000000000423a151 mlir::MlirOptMain(llvm::raw_ostream&, std::unique_ptr<llvm::MemoryBuffer, std::default_delete<llvm::MemoryBuffer> >, mlir::DialectRegistry&, mlir::MlirOptMainConfig const&) (/home/fuzzing/llvm-project/build/bin/mlir-opt+0x423a151)
#26 0x000000000423a403 mlir::MlirOptMain(int, char**, llvm::StringRef, llvm::StringRef, mlir::DialectRegistry&) (/home/fuzzing/llvm-project/build/bin/mlir-opt+0x423a403)
#27 0x000000000423a612 mlir::MlirOptMain(int, char**, llvm::StringRef, mlir::DialectRegistry&) (/home/fuzzing/llvm-project/build/bin/mlir-opt+0x423a612)
#28 0x000000000111a8d7 main (/home/fuzzing/llvm-project/build/bin/mlir-opt+0x111a8d7)
#29 0x00007b2d50408d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#30 0x00007b2d50408e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#31 0x000000000111a435 _start (/home/fuzzing/llvm-project/build/bin/mlir-opt+0x111a435)
Segmentation fault (core dumped)
```
</pre>
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