[mlir] Assertion '__builtin_expect(__n < this->size(), true)' failed.

git version: 81a8c66fdc96a7bf6927bf3f88d4b2e24a5c71e7

system: `Ubuntu 18.04.6 LTS`

reproduce with: `mlir-opt -form-expressions a.mlir`

a.mlir:

```mlir
module {
func.func @minsi(%arg0: i32, %arg1: i32) -> i32 {
%0 = emitc.call_opaque "minsi"(%arg0, %arg0, %arg1) : (i32, i32, i32) -> i32
return %0 : i32
}
}

```

stack trace:

```
/usr/lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/stl_vector.h:1042: reference std::vector::operator[](size_type) [_Tp = mlir::BlockArgument, _Alloc = std::allocator]: Assertion '__builtin_expect(__n < this->size(), true)' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and instructions to reproduce the bug.
Stack dump:
0. Program arguments: /data/szy/MLIR/llvm-release/llvm-project/build/bin/mlir-opt -form-expressions 67.mlir
#0 0x000055a19e8260c8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/data/szy/MLIR/llvm-release/llvm-project/build/bin/mlir-opt+0x20360c8)
#1 0x000055a19e822f61 llvm::sys::RunSignalHandlers() (/data/szy/MLIR/llvm-release/llvm-project/build/bin/mlir-opt+0x2032f61)
#2 0x000055a19e8271e6 SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
#3 0x00007f0e1dae3420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)
#4 0x00007f0e1d12000b raise /build/glibc-LcI20x/glibc-2.31/signal/../sysdeps/unix/sysv/linux/raise.c:51:1
#5 0x00007f0e1d0ff859 abort /build/glibc-LcI20x/glibc-2.31/stdlib/abort.c:81:7
#6 0x000055a1a4a2dfe2 (anonymous namespace)::RemoveRecurringExpressionOperands::matchAndRewrite(mlir::emitc::ExpressionOp, mlir::PatternRewriter&) const EmitC.cpp:0:0
#7 0x000055a1a71b327d void llvm::function_ref::callback_fn, llvm::function_ref, llvm::function_ref)::$_0>(long) PatternApplicator.cpp:0:0
#8 0x000055a1a71afbda mlir::PatternApplicator::matchAndRewrite(mlir::Operation*, mlir::PatternRewriter&, llvm::function_ref, llvm::function_ref, llvm::function_ref) (/data/szy/MLIR/llvm-release/llvm-project/build/bin/mlir-opt+0xa9bfbda)
#9 0x000055a1a71884b4 (anonymous namespace)::GreedyPatternRewriteDriver::processWorklist() GreedyPatternRewriteDriver.cpp:0:0
#10 0x000055a1a7187532 void llvm::function_ref::callback_fn<(anonymous namespace)::RegionPatternRewriteDriver::simplify(bool*) &&::$_2>(long) GreedyPatternRewriteDriver.cpp:0:0
#11 0x000055a1a718451b mlir::applyPatternsGreedily(mlir::Region&, mlir::FrozenRewritePatternSet const&, mlir::GreedyRewriteConfig, bool*) (/data/szy/MLIR/llvm-release/llvm-project/build/bin/mlir-opt+0xa99451b)
#12 0x000055a1a0734db8 (anonymous namespace)::FormExpressionsPass::runOnOperation() FormExpressions.cpp:0:0
#13 0x000055a1a720e662 mlir::detail::OpToOpPassAdaptor::run(mlir::Pass*, mlir::Operation*, mlir::AnalysisManager, bool, unsigned int) (/data/szy/MLIR/llvm-release/llvm-project/build/bin/mlir-opt+0xaa1e662)
#14 0x000055a1a720f4a4 mlir::detail::OpToOpPassAdaptor::runPipeline(mlir::OpPassManager&, mlir::Operation*, mlir::AnalysisManager, bool, unsigned int, mlir::PassInstrumentor*, mlir::PassInstrumentation::PipelineParentInfo const*) (/data/szy/MLIR/llvm-release/llvm-project/build/bin/mlir-opt+0xaa1f4a4)
#15 0x000055a1a72163ba mlir::PassManager::runPasses(mlir::Operation*, mlir::AnalysisManager) (/data/szy/MLIR/llvm-release/llvm-project/build/bin/mlir-opt+0xaa263ba)
#16 0x000055a1a7215cef mlir::PassManager::run(mlir::Operation*) (/data/szy/MLIR/llvm-release/llvm-project/build/bin/mlir-opt+0xaa25cef)
#17 0x000055a19e8d53c0 performActions(llvm::raw_ostream&, std::shared_ptr const&, mlir::MLIRContext*, mlir::MlirOptMainConfig const&) MlirOptMain.cpp:0:0
#18 0x000055a19e8d45f6 llvm::LogicalResult llvm::function_ref>, llvm::MemoryBufferRef const&, llvm::raw_ostream&)>::callback_fn>, mlir::DialectRegistry&, mlir::MlirOptMainConfig const&)::$_0>(long, std::unique_ptr>, llvm::MemoryBufferRef const&, llvm::raw_ostream&) MlirOptMain.cpp:0:0
#19 0x000055a1a7561e55 mlir::splitAndProcessBuffer(std::unique_ptr>, llvm::function_ref>, llvm::MemoryBufferRef const&, llvm::raw_ostream&)>, llvm::raw_ostream&, llvm::StringRef, llvm::StringRef) (/data/szy/MLIR/llvm-release/llvm-project/build/bin/mlir-opt+0xad71e55)
#20 0x000055a19e8cb656 mlir::MlirOptMain(llvm::raw_ostream&, std::unique_ptr>, mlir::DialectRegistry&, mlir::MlirOptMainConfig const&) (/data/szy/MLIR/llvm-release/llvm-project/build/bin/mlir-opt+0x20db656)
#21 0x000055a19e8cba35 mlir::MlirOptMain(int, char**, llvm::StringRef, llvm::StringRef, mlir::DialectRegistry&) (/data/szy/MLIR/llvm-release/llvm-project/build/bin/mlir-opt+0x20dba35)
#22 0x000055a19e8cbd95 mlir::MlirOptMain(int, char**, llvm::StringRef, mlir::DialectRegistry&) (/data/szy/MLIR/llvm-release/llvm-project/build/bin/mlir-opt+0x20dbd95)
#23 0x000055a19e80bb52 main (/data/szy/MLIR/llvm-release/llvm-project/build/bin/mlir-opt+0x201bb52)
#24 0x00007f0e1d101083 __libc_start_main /build/glibc-LcI20x/glibc-2.31/csu/../csu/libc-start.c:342:3
#25 0x000055a19e80b68e _start (/data/szy/MLIR/llvm-release/llvm-project/build/bin/mlir-opt+0x201b68e)
Aborted (core dumped)
```

Reproduce the crash with mlir-opt -form-expressions a.mlir, then inspect RemoveRecurringExpressionOperands::matchAndRewrite in EmitC.cpp and the FormExpressionsPass in FormExpressions.cpp. Trace how the provided emitc.call_opaque operands reach the vector access. Done means the input no longer aborts with the assertion and the behavior is covered by an appropriate regression test.

Written by the indexing model from the issue text.