[SCFToCalyx] Cannot lower to Calyx with memref.global

The --lower-scf-to-calyx pass fails with a seg fault:

module {
memref.global "private" @conv_weight : memref<600xf32> = dense<"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
   func.func @test() -> i32{
       %0 = arith.constant 1 : i32

       %1 = memref.get_global @conv_weight : memref<600xf32>

       %2 = arith.sitofp %0 : i32 to f32
       %3 = arith.index_cast %0 : i32 to index
       memref.store %2, %1[%3] : memref<600xf32>

       %4 = arith.addf %2, %2 : f32

       %5 = arith.fptosi %4 : f32 to i32

       return %0 : i32
   }
}

The stack dump:

0.	Program arguments: /opt/compiler-explorer/circt-trunk/bin/circt-opt -o /app/example.out.mlir --pass-pipeline=builtin.module(lower-scf-to-calyx{top-level-function=test}) <source>
 #0 0x0000000001414b58 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/circt-trunk/bin/circt-opt+0x1414b58)
 #1 0x0000000001411835 SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
 #2 0x00007f518a842520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #3 0x0000000002ed482b mlir::DenseElementsAttr::getNumElements() const (/opt/compiler-explorer/circt-trunk/bin/circt-opt+0x2ed482b)
 #4 0x0000000002cd36a8 llvm::LogicalResult circt::scftocalyx::buildAllocOp<mlir::memref::GetGlobalOp>(circt::scftocalyx::ComponentLoweringState&, mlir::PatternRewriter&, mlir::memref::GetGlobalOp) SCFToCalyx.cpp:0:0
 #5 0x0000000002cd472d circt::scftocalyx::BuildOpGroups::partiallyLowerFuncToComp(mlir::func::FuncOp, mlir::PatternRewriter&) const::'lambda'(mlir::Operation*)::operator()(mlir::Operation*) const (/opt/compiler-explorer/circt-trunk/bin/circt-opt+0x2cd472d)
 #6 0x0000000002cd5840 mlir::WalkResult mlir::detail::walk<mlir::ForwardIterator>(mlir::Operation*, llvm::function_ref<mlir::WalkResult (mlir::Operation*)>, mlir::WalkOrder) (.constprop.5) SCFToCalyx.cpp:0:0
 #7 0x0000000002cd5814 mlir::WalkResult mlir::detail::walk<mlir::ForwardIterator>(mlir::Operation*, llvm::function_ref<mlir::WalkResult (mlir::Operation*)>, mlir::WalkOrder) (.constprop.5) SCFToCalyx.cpp:0:0
 #8 0x0000000002cd58e3 circt::scftocalyx::BuildOpGroups::partiallyLowerFuncToComp(mlir::func::FuncOp, mlir::PatternRewriter&) const (/opt/compiler-explorer/circt-trunk/bin/circt-opt+0x2cd58e3)
 #9 0x0000000002c1f283 circt::calyx::PartialLoweringPattern<mlir::func::FuncOp, mlir::OpRewritePattern>::matchAndRewrite(mlir::func::FuncOp, mlir::PatternRewriter&) const (/opt/compiler-explorer/circt-trunk/bin/circt-opt+0x2c1f283)
#10 0x0000000003b35192 mlir::PatternApplicator::matchAndRewrite(mlir::Operation*, mlir::PatternRewriter&, llvm::function_ref<bool (mlir::Pattern const&)>, llvm::function_ref<void (mlir::Pattern const&)>, llvm::function_ref<llvm::LogicalResult (mlir::Pattern const&)>)::'lambda'()::operator()() const PatternApplicator.cpp:0:0
#11 0x0000000003b3653a mlir::PatternApplicator::matchAndRewrite(mlir::Operation*, mlir::PatternRewriter&, llvm::function_ref<bool (mlir::Pattern const&)>, llvm::function_ref<void (mlir::Pattern const&)>, llvm::function_ref<llvm::LogicalResult (mlir::Pattern const&)>) (/opt/compiler-explorer/circt-trunk/bin/circt-opt+0x3b3653a)
#12 0x0000000003b03cb3 (anonymous namespace)::GreedyPatternRewriteDriver::processWorklist() GreedyPatternRewriteDriver.cpp:0:0
#13 0x0000000003b084b3 mlir::applyPatternsGreedily(mlir::Region&, mlir::FrozenRewritePatternSet const&, mlir::GreedyRewriteConfig, bool*) (/opt/compiler-explorer/circt-trunk/bin/circt-opt+0x3b084b3)
#14 0x0000000002cded27 circt::(anonymous namespace)::SCFToCalyxPass::runOnOperation() SCFToCalyx.cpp:0:0
#15 0x0000000003c45fa1 mlir::detail::OpToOpPassAdaptor::run(mlir::Pass*, mlir::Operation*, mlir::AnalysisManager, bool, unsigned int) (/opt/compiler-explorer/circt-trunk/bin/circt-opt+0x3c45fa1)
#16 0x0000000003c462d7 mlir::detail::OpToOpPassAdaptor::runPipeline(mlir::OpPassManager&, mlir::Operation*, mlir::AnalysisManager, bool, unsigned int, mlir::PassInstrumentor*, mlir::PassInstrumentation::PipelineParentInfo const*) (/opt/compiler-explorer/circt-trunk/bin/circt-opt+0x3c462d7)
#17 0x0000000003c480ba mlir::PassManager::runPasses(mlir::Operation*, mlir::AnalysisManager) (/opt/compiler-explorer/circt-trunk/bin/circt-opt+0x3c480ba)
#18 0x0000000003c48f31 mlir::PassManager::run(mlir::Operation*) (/opt/compiler-explorer/circt-trunk/bin/circt-opt+0x3c48f31)
#19 0x000000000344a637 performActions(llvm::raw_ostream&, std::shared_ptr<llvm::SourceMgr> const&, mlir::MLIRContext*, mlir::MlirOptMainConfig const&) MlirOptMain.cpp:0:0
#20 0x000000000344b047 llvm::LogicalResult llvm::function_ref<llvm::LogicalResult (std::unique_ptr<llvm::MemoryBuffer, std::default_delete<llvm::MemoryBuffer>>, llvm::MemoryBufferRef const&, 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&)::'lambda'(std::unique_ptr<llvm::MemoryBuffer, std::default_delete<llvm::MemoryBuffer>>, llvm::MemoryBufferRef, llvm::raw_ostream&)>(long, std::unique_ptr<llvm::MemoryBuffer, std::default_delete<llvm::MemoryBuffer>>, llvm::MemoryBufferRef const&, llvm::raw_ostream&) MlirOptMain.cpp:0:0
#21 0x000000000347eafe 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::MemoryBufferRef const&, llvm::raw_ostream&)>, llvm::raw_ostream&, llvm::StringRef, llvm::StringRef) (/opt/compiler-explorer/circt-trunk/bin/circt-opt+0x347eafe)
#22 0x0000000003446a89 mlir::MlirOptMain(llvm::raw_ostream&, std::unique_ptr<llvm::MemoryBuffer, std::default_delete<llvm::MemoryBuffer>>, mlir::DialectRegistry&, mlir::MlirOptMainConfig const&) (.part.0) MlirOptMain.cpp:0:0
#23 0x000000000344b7a4 mlir::MlirOptMain(int, char**, llvm::StringRef, llvm::StringRef, mlir::DialectRegistry&) (/opt/compiler-explorer/circt-trunk/bin/circt-opt+0x344b7a4)
#24 0x000000000344b9ed mlir::MlirOptMain(int, char**, llvm::StringRef, mlir::DialectRegistry&) (/opt/compiler-explorer/circt-trunk/bin/circt-opt+0x344b9ed)
#25 0x000000000137819d main (/opt/compiler-explorer/circt-trunk/bin/circt-opt+0x137819d)
#26 0x00007f518a829d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#27 0x00007f518a829e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#28 0x000000000137c445 _start (/opt/compiler-explorer/circt-trunk/bin/circt-opt+0x137c445)

The issue is likely not checking for null before trying to call getValues()

 auto cstAttr = llvm::dyn_cast_or_null<DenseElementsAttr>(
        globalOp.getConstantInitValue());
    int sizeCount = 0;
    for (auto attr : cstAttr.template getValues<Attribute>()) {
      assert((isa<mlir::FloatAttr, mlir::IntegerAttr>(attr)) &&
             "memory attributes must be float or int");
      if (auto fltAttr = dyn_cast<mlir::FloatAttr>(attr)) {
        flattenedVals[sizeCount++] =
            bit_cast<uint64_t>(fltAttr.getValueAsDouble());
      } else {
        auto intAttr = dyn_cast<mlir::IntegerAttr>(attr);
        APInt value = intAttr.getValue();
        flattenedVals[sizeCount++] = *value.getRawData();
      }
    }

Start in SCFToCalyx.cpp at buildAllocOp and inspect how memref.get_global handles globalOp.getConstantInitValue(). Reproduce the crash with the supplied MLIR and the lower-scf-to-calyx{top-level-function=test} pipeline. Done means the pass no longer segfaults on this input and its behavior for the missing constant initializer is handled safely.