[flang] Generate TBAA information.

[vzakhari]

Summary

This is initial version of TBAA information generation for Flang
generated IR. The desired behavior is that TBAA type descriptors
are generated for FIR types during FIR to LLVM types conversion,
and then TBAA access tags are attached to memory accessing operations
when they are converted to LLVM IR dialect.

In the initial version the type conversion is not producing
TBAA type descriptors, and all memory accesses are just partitioned
into two sets of box and non-box accesses, which can never alias.

The TBAA generation is enabled by default at >O0 optimization levels.
TBAA generation may also be enabled via apply-tbaa option of
fir-to-llvm-ir conversion pass. -mllvm -disable-tbaa engineering
option allows disabling TBAA generation to override Flang's default
(e.g. when -O1 is used).

SPEC CPU2006/437.leslie3d speeds up by more than 2x on Icelake.

Depends on D141726

[jeanPerier]

I am not knowledgeable on TBAA, so I cannot asses if the metadata is created correctly, but the explanation an code adding the attributes in codegen looks great. Nice to see it has a measurable impact on performance too! (Something is wrong with the windows bot build, but I think you may just need to rebase, many other patched had similar windows failures today).

[vzakhari]

Thank you for the review, Jean! Yes, it looks like Windows buildbot has been failing for a couple of days, but it should be okay after 7bf1e441da6b59a25495fde8e34939f93548cc6d. I will upload rebased files shortly.

flang/lib/Optimizer/CodeGen/CodeGen.cpp

1634

I believe it should be sourceBoxType instead of boxTy here and in the next call, because they are generating accesses of the sourceBox. I noticed this during the rebase and fixed.

[vzakhari]

• rebase

[clementval]

flang/lib/Optimizer/CodeGen/CodeGen.cpp

1634

Yeah sourceBoxType sounds right here.

[PeteSteinfeld]

A few nits.

flang/lib/Optimizer/CodeGen/TBAABuilder.cpp

39

Should read "In the usual"

flang/lib/Optimizer/CodeGen/TBAABuilder.h

24

Should read "type conversion and to attach llvm.tbaa attributes to memory access"

43

"parent" rather than "parrent"

47

Should read "whether an operation"

103

Should read "has to provide"

109

Did you mean to say "access's"?

152

Should read "in an incorrect result" and "in the scope"

157

Should read "under the opt-in"

172

Should read "Attach the llvm.tbaa"

[vzakhari]

Thank you for the comments, @PeteSteinfeld! I will upload the updated files shortly.

flang/lib/Optimizer/CodeGen/TBAABuilder.h

109

I did, but I thought the final s had to be dropped. Thanks!

157

I would prefer under an opt-in, because the option is not defined.

[vzakhari]

• Fixed the wording.

[peixin]

Hi @vzakhari , are you still working on box/type descriptor such as type_desc_4/5/6? Or do you plan to work on that later? I am studying some optimizations which may benefit from the complete tbaa.

[vzakhari]

In D141820#4221238, @peixin wrote:

Hi @vzakhari , are you still working on box/type descriptor such as type_desc_4/5/6? Or do you plan to work on that later? I am studying some optimizations which may benefit from the complete tbaa.

Hi @peixin, I am not working on this. Can you please share the cases where you think it might be profitable to distinguish boxes with different number of dimensions? Is it from real applications? We can discuss it in email - it seems more convenient.

[kiranchandramohan]

In D141820#4224901, @vzakhari wrote:

In D141820#4221238, @peixin wrote:

Hi @vzakhari , are you still working on box/type descriptor such as type_desc_4/5/6? Or do you plan to work on that later? I am studying some optimizations which may benefit from the complete tbaa.

Hi @peixin, I am not working on this. Can you please share the cases where you think it might be profitable to distinguish boxes with different number of dimensions? Is it from real applications? We can discuss it in email - it seems more convenient.

@SBallantyne also ran into some cases where additional tbaa information is useful. It is not clear yet whether this involves tbaa for dummy arguments as well. If we can discuss this in discourse that would be great since we can also participate or stay informed.

[peixin]

In D141820#4224901, @vzakhari wrote:

In D141820#4221238, @peixin wrote:

Hi @vzakhari , are you still working on box/type descriptor such as type_desc_4/5/6? Or do you plan to work on that later? I am studying some optimizations which may benefit from the complete tbaa.

Hi @peixin, I am not working on this. Can you please share the cases where you think it might be profitable to distinguish boxes with different number of dimensions? Is it from real applications? We can discuss it in email - it seems more convenient.

Yes, it's from one real application, and the hot loop is from one specific input. The loop is like the following where a is assumed shape array, and b is explicit-shape array. To perform the loop interchange optimization, one problem is that it is hard to understand the loop structure from the SCEV of a(i, k) access. I am thinking if the tbaa lower bound, upper bound and stride would help.

DO j=Jstart, Jend
  DO i=Istart, Iend
    DO k=1, N
      a(i,k)=0.5_8*(b(i-1,j,k) + b(i  ,j,k))
    END DO
  END DO
END DO

[peixin]

@SBallantyne also ran into some cases where additional tbaa information is useful. It is not clear yet whether this involves tbaa for dummy arguments as well. If we can discuss this in discourse that would be great since we can also participate or stay informed.

@kiranchandramohan @SBallantyne I am still analyzing it, and am not ready to give one clear result of how to utilize the tbaa dimentional info. I prepare to generate one by hand and proceed the analysis.

[kiranchandramohan]

In D141820#4226210, @peixin wrote:

@SBallantyne also ran into some cases where additional tbaa information is useful. It is not clear yet whether this involves tbaa for dummy arguments as well. If we can discuss this in discourse that would be great since we can also participate or stay informed.

@kiranchandramohan @SBallantyne I am still analyzing it, and am not ready to give one clear result of how to utilize the tbaa dimentional info. I prepare to generate one by hand and proceed the analysis.

Thanks @peixin. We were looking at some kernels from lapack. Some of the complex type kernels give an order-of-magnitude slowdown compared to classic-flang. We see plenty of memchecks generated by the llvm vectorizer for an inner loop. But these were not present for the real type kernels. We are not yet sure whether these are caused by a lack of alias info or something specific to the Complex vectorisation in llvm.

In D141820#4226126, @peixin wrote:

In D141820#4224901, @vzakhari wrote:

In D141820#4221238, @peixin wrote:

Hi @vzakhari , are you still working on box/type descriptor such as type_desc_4/5/6? Or do you plan to work on that later? I am studying some optimizations which may benefit from the complete tbaa.

Hi @peixin, I am not working on this. Can you please share the cases where you think it might be profitable to distinguish boxes with different number of dimensions? Is it from real applications? We can discuss it in email - it seems more convenient.

Yes, it's from one real application, and the hot loop is from one specific input. The loop is like the following where a is assumed shape array, and b is explicit-shape array. To perform the loop interchange optimization, one problem is that it is hard to understand the loop structure from the SCEV of a(i, k) access. I am thinking if the tbaa lower bound, upper bound and stride would help.

DO j=Jstart, Jend
  DO i=Istart, Iend
    DO k=1, N
      a(i,k)=0.5_8*(b(i-1,j,k) + b(i  ,j,k))
    END DO
  END DO
END DO

I remember engineers from another organisation passing additional info from Classic-Flang to LLVM to make SCEV aware of descriptor info. It was a few years ago so I don't remember the details.

An alternative (as you know) would be to do the interchange in MLIR itself by promoting (if possible) to Affine. I don't know whether the present infrastructure is sufficient for it.

[peixin]

Thanks @peixin. We were looking at some kernels from lapack. Some of the complex type kernels give an order-of-magnitude slowdown compared to classic-flang. We see plenty of memchecks generated by the llvm vectorizer for an inner loop. But these were not present for the real type kernels. We are not yet sure whether these are caused by a lack of alias info or something specific to the Complex vectorisation in llvm.

@kiranchandramohan Is someone working on it? If not, can you send me one test case and I can take a look at it. I am also investigating the SCEV and mem checks for Fortran IR (both LLVM Flang and Classic Flang) in LV pass.

I remember engineers from another organisation passing additional info from Classic-Flang to LLVM to make SCEV aware of descriptor info. It was a few years ago so I don't remember the details.

An alternative (as you know) would be to do the interchange in MLIR itself by promoting (if possible) to Affine. I don't know whether the present infrastructure is sufficient for it.

True, doing the interchange in MLIR may be easier. But I am trying to find some way benefiting both LLVM Flang and Classic Flang. So I have to work on llvm pass.

[kiranchandramohan]

In D141820#4233097, @peixin wrote:

Thanks @peixin. We were looking at some kernels from lapack. Some of the complex type kernels give an order-of-magnitude slowdown compared to classic-flang. We see plenty of memchecks generated by the llvm vectorizer for an inner loop. But these were not present for the real type kernels. We are not yet sure whether these are caused by a lack of alias info or something specific to the Complex vectorisation in llvm.

@kiranchandramohan Is someone working on it? If not, can you send me one test case and I can take a look at it. I am also investigating the SCEV and mem checks for Fortran IR (both LLVM Flang and Classic Flang) in LV pass.

@SBallantyne was investigating this. He found out that we have some downstream llvm changes that reduce the number of runtime memory checks in some strided cases. A WIP patch is available in https://reviews.llvm.org/D147542.

I remember engineers from another organisation passing additional info from Classic-Flang to LLVM to make SCEV aware of descriptor info. It was a few years ago so I don't remember the details.

An alternative (as you know) would be to do the interchange in MLIR itself by promoting (if possible) to Affine. I don't know whether the present infrastructure is sufficient for it.

True, doing the interchange in MLIR may be easier. But I am trying to find some way benefiting both LLVM Flang and Classic Flang. So I have to work on llvm pass.

OK.

[vzakhari]

In D141820#4226126, @peixin wrote:

In D141820#4224901, @vzakhari wrote:

In D141820#4221238, @peixin wrote:

Hi @vzakhari , are you still working on box/type descriptor such as type_desc_4/5/6? Or do you plan to work on that later? I am studying some optimizations which may benefit from the complete tbaa.

Hi @peixin, I am not working on this. Can you please share the cases where you think it might be profitable to distinguish boxes with different number of dimensions? Is it from real applications? We can discuss it in email - it seems more convenient.

Yes, it's from one real application, and the hot loop is from one specific input. The loop is like the following where a is assumed shape array, and b is explicit-shape array. To perform the loop interchange optimization, one problem is that it is hard to understand the loop structure from the SCEV of a(i, k) access. I am thinking if the tbaa lower bound, upper bound and stride would help.

DO j=Jstart, Jend
  DO i=Istart, Iend
    DO k=1, N
      a(i,k)=0.5_8*(b(i-1,j,k) + b(i  ,j,k))
    END DO
  END DO
END DO

Hi @peixin, sorry, I do not understand how more specific tbaa for the members of the descriptor can help here. This loop has a single "data" store for a(i,k). The loads of the descriptor members are also inside the loop, but the current tbaa should allow disambiguating the data store with the member loads. So LLVM should be able to hoist the member loads from the loop nest with the current tbaa, since they are invariants.

I suppose the load from N might be a problem for the loop interchange, since the current tbaa does not help disambiguating load from N with the store to a(i,k) inside the outer loop. But having more precise tbaa for the descriptor members won't help here as well.

[peixin]

In D141820#4243777, @vzakhari wrote:

In D141820#4226126, @peixin wrote:

In D141820#4224901, @vzakhari wrote:

In D141820#4221238, @peixin wrote:

Hi @vzakhari , are you still working on box/type descriptor such as type_desc_4/5/6? Or do you plan to work on that later? I am studying some optimizations which may benefit from the complete tbaa.

Hi @peixin, I am not working on this. Can you please share the cases where you think it might be profitable to distinguish boxes with different number of dimensions? Is it from real applications? We can discuss it in email - it seems more convenient.

Yes, it's from one real application, and the hot loop is from one specific input. The loop is like the following where a is assumed shape array, and b is explicit-shape array. To perform the loop interchange optimization, one problem is that it is hard to understand the loop structure from the SCEV of a(i, k) access. I am thinking if the tbaa lower bound, upper bound and stride would help.

DO j=Jstart, Jend
  DO i=Istart, Iend
    DO k=1, N
      a(i,k)=0.5_8*(b(i-1,j,k) + b(i  ,j,k))
    END DO
  END DO
END DO

Hi @peixin, sorry, I do not understand how more specific tbaa for the members of the descriptor can help here. This loop has a single "data" store for a(i,k). The loads of the descriptor members are also inside the loop, but the current tbaa should allow disambiguating the data store with the member loads. So LLVM should be able to hoist the member loads from the loop nest with the current tbaa, since they are invariants.

I suppose the load from N might be a problem for the loop interchange, since the current tbaa does not help disambiguating load from N with the store to a(i,k) inside the outer loop. But having more precise tbaa for the descriptor members won't help here as well.

I think you are talking about the dependence analysis in loop interchange. The loop interchange pass is not enabled by default, and it heavily realies on the IR input according to my experiences and the cost model is updated last year. The problem I faced is not the dependence analysis. I used SCEV to analyze the loop structure and succeed when I work in classic-flang. But it causes some regression in some complex IR. So I am thinking if I can use the TBAA to restrict the SCEV analysis to special cases. I mean to restrict the SCEV analysis for only fortran array addressing.

flang/include/flang/Optimizer/CodeGen/CGPasses.td

def FIRToLLVMLowering : Pass<"fir-to-llvm-ir", "mlir::ModuleOp"> {
   let description = [{
     Convert the FIR dialect to the LLVM-IR dialect of MLIR. This conversion
     will also convert ops in the standard and FIRCG dialects.
   }];
   let constructor = "::fir::createFIRToLLVMPass()";
   let dependentDialects = ["mlir::LLVM::LLVMDialect"];
   let options = [
     Option<"forcedTargetTriple", "target", "std::string", /*default=*/"",
-           "Override module's target triple.">
+           "Override module's target triple.">,
+    Option<"applyTBAA", "apply-tbaa", "bool", /*default=*/"false",
+           "Attach TBAA tags to memory accessing operations.">
   ];
 }
 
 def CodeGenRewrite : Pass<"cg-rewrite", "mlir::ModuleOp"> {
   let summary = "Rewrite some FIR ops into their code-gen forms.";
   let description = [{
     Fuse specific subgraphs into single Ops for code generation.
   }];

flang/include/flang/Optimizer/CodeGen/CodeGen.h

struct FIRToLLVMPassOptions {
   // Do not fail when type descriptors are not found when translating
   // operations that use them at the LLVM level like fir.embox. Instead,
   // just use a null pointer.
   // This is useful to test translating programs manually written where a
   // frontend did not generate type descriptor data structures. However, note
   // that such programs would crash at runtime if the derived type descriptors
   // are required by the runtime, so this is only an option to help debugging.
   bool ignoreMissingTypeDescriptors = false;
+
+  // Generate TBAA information for FIR types and memory accessing operations.
+  bool applyTBAA = false;
 };
 
 /// Convert FIR to the LLVM IR dialect with default options.
 std::unique_ptr<mlir::Pass> createFIRToLLVMPass();
 
 /// Convert FIR to the LLVM IR dialect
 std::unique_ptr<mlir::Pass> createFIRToLLVMPass(FIRToLLVMPassOptions options);
 

flang/include/flang/Tools/CLOptions.inc

inline void addTargetRewritePass(mlir::PassManager &pm) {
   });
 }
 
 inline void addDebugFoundationPass(mlir::PassManager &pm) {
   addPassConditionally(pm, disableDebugFoundation,
       [&]() { return fir::createAddDebugFoundationPass(); });
 }
 
-inline void addFIRToLLVMPass(mlir::PassManager &pm) {
+inline void addFIRToLLVMPass(
+    mlir::PassManager &pm, llvm::OptimizationLevel optLevel = defaultOptLevel) {
   fir::FIRToLLVMPassOptions options;
   options.ignoreMissingTypeDescriptors = ignoreMissingTypeDescriptors;
+  options.applyTBAA = optLevel.isOptimizingForSpeed();
   addPassConditionally(pm, disableFirToLlvmIr,
       [&]() { return fir::createFIRToLLVMPass(options); });
 }
 
 inline void addLLVMDialectToLLVMPass(
     mlir::PassManager &pm, llvm::raw_ostream &output) {
   addPassConditionally(pm, disableLlvmIrToLlvm,
       [&]() { return fir::createLLVMDialectToLLVMPass(output); });
inline void createDefaultFIROptimizerPassPipeline(
   pm.addPass(mlir::createConvertSCFToCFPass());
 
   pm.addPass(mlir::createCanonicalizerPass(config));
   pm.addPass(fir::createSimplifyRegionLitePass());
   pm.addPass(mlir::createCSEPass());
 }
 
 #if !defined(FLANG_EXCLUDE_CODEGEN)
-inline void createDefaultFIRCodeGenPassPipeline(mlir::PassManager &pm) {
+inline void createDefaultFIRCodeGenPassPipeline(
+    mlir::PassManager &pm, llvm::OptimizationLevel optLevel = defaultOptLevel) {
   fir::addBoxedProcedurePass(pm);
   pm.addNestedPass<mlir::func::FuncOp>(
       fir::createAbstractResultOnFuncOptPass());
   pm.addNestedPass<fir::GlobalOp>(
       fir::createAbstractResultOnGlobalOptPass());
   fir::addCodeGenRewritePass(pm);
   fir::addTargetRewritePass(pm);
   fir::addExternalNameConversionPass(pm);
-  fir::addFIRToLLVMPass(pm);
+  fir::addFIRToLLVMPass(pm, optLevel);
 }
 
 /// Create a pass pipeline for lowering from MLIR to LLVM IR
 ///
 /// \param pm - MLIR pass manager that will hold the pipeline definition
 /// \param optLevel - optimization level used for creating FIR optimization
 ///   passes pipeline
 inline void createMLIRToLLVMPassPipeline(
     mlir::PassManager &pm, llvm::OptimizationLevel optLevel = defaultOptLevel) {
   // Add default optimizer pass pipeline.
   fir::createDefaultFIROptimizerPassPipeline(pm, optLevel);
 
   // Add codegen pass pipeline.
-  fir::createDefaultFIRCodeGenPassPipeline(pm);
+  fir::createDefaultFIRCodeGenPassPipeline(pm, optLevel);
 }
 #undef FLANG_EXCLUDE_CODEGEN
 #endif
 
 } // namespace fir

flang/lib/Optimizer/CodeGen/CMakeLists.txt

 add_flang_library(FIRCodeGen
   BoxedProcedure.cpp
   CGOps.cpp
   CodeGen.cpp
   PreCGRewrite.cpp
+  TBAABuilder.cpp
   Target.cpp
   TargetRewrite.cpp
 
   DEPENDS
   FIRBuilder
   FIRDialect
   FIRSupport
   FIROptCodeGenPassIncGen

flang/lib/Optimizer/CodeGen/CodeGen.cpp

mlir::Value integerCast(mlir::Location loc,
     auto fromSize = mlir::LLVM::getPrimitiveTypeSizeInBits(valTy);
     if (toSize < fromSize)
       return rewriter.create<mlir::LLVM::TruncOp>(loc, ty, val);
     if (toSize > fromSize)
       return rewriter.create<mlir::LLVM::SExtOp>(loc, ty, val);
     return val;
   }
 
-  /// Construct code sequence to extract the specifc value from a `fir.box`.
-  mlir::Value getValueFromBox(mlir::Location loc, mlir::Value box,
-                              mlir::Type resultTy,
+  /// Construct code sequence to extract the specific value from a `fir.box`.
+  mlir::Value getValueFromBox(mlir::Location loc, mlir::Type boxTy,
+                              mlir::Value box, mlir::Type resultTy,
                               mlir::ConversionPatternRewriter &rewriter,
                               int boxValue) const {
     if (box.getType().isa<mlir::LLVM::LLVMPointerType>()) {
       auto pty = mlir::LLVM::LLVMPointerType::get(resultTy);
       auto p = rewriter.create<mlir::LLVM::GEPOp>(
           loc, pty, box, llvm::ArrayRef<mlir::LLVM::GEPArg>{0, boxValue});
-      return rewriter.create<mlir::LLVM::LoadOp>(loc, resultTy, p);
+      auto loadOp = rewriter.create<mlir::LLVM::LoadOp>(loc, resultTy, p);
+      attachTBAATag(loadOp, boxTy, nullptr, p);
+      return loadOp;
     }
     return rewriter.create<mlir::LLVM::ExtractValueOp>(loc, box, boxValue);
   }
 
   /// Method to construct code sequence to get the triple for dimension `dim`
   /// from a box.
   llvm::SmallVector<mlir::Value, 3>
   getDimsFromBox(mlir::Location loc, llvm::ArrayRef<mlir::Type> retTys,
-                 mlir::Value box, mlir::Value dim,
+                 mlir::Type boxTy, mlir::Value box, mlir::Value dim,
                  mlir::ConversionPatternRewriter &rewriter) const {
-    mlir::Value l0 = loadDimFieldFromBox(loc, box, dim, 0, retTys[0], rewriter);
-    mlir::Value l1 = loadDimFieldFromBox(loc, box, dim, 1, retTys[1], rewriter);
-    mlir::Value l2 = loadDimFieldFromBox(loc, box, dim, 2, retTys[2], rewriter);
+    mlir::Value l0 =
+        loadDimFieldFromBox(loc, boxTy, box, dim, 0, retTys[0], rewriter);
+    mlir::Value l1 =
+        loadDimFieldFromBox(loc, boxTy, box, dim, 1, retTys[1], rewriter);
+    mlir::Value l2 =
+        loadDimFieldFromBox(loc, boxTy, box, dim, 2, retTys[2], rewriter);
     return {l0, l1, l2};
   }
 
   llvm::SmallVector<mlir::Value, 3>
   getDimsFromBox(mlir::Location loc, llvm::ArrayRef<mlir::Type> retTys,
-                 mlir::Value box, int dim,
+                 mlir::Type boxTy, mlir::Value box, int dim,
                  mlir::ConversionPatternRewriter &rewriter) const {
-    mlir::Value l0 = getDimFieldFromBox(loc, box, dim, 0, retTys[0], rewriter);
-    mlir::Value l1 = getDimFieldFromBox(loc, box, dim, 1, retTys[1], rewriter);
-    mlir::Value l2 = getDimFieldFromBox(loc, box, dim, 2, retTys[2], rewriter);
+    mlir::Value l0 =
+        getDimFieldFromBox(loc, boxTy, box, dim, 0, retTys[0], rewriter);
+    mlir::Value l1 =
+        getDimFieldFromBox(loc, boxTy, box, dim, 1, retTys[1], rewriter);
+    mlir::Value l2 =
+        getDimFieldFromBox(loc, boxTy, box, dim, 2, retTys[2], rewriter);
     return {l0, l1, l2};
   }
 
   mlir::Value
-  loadDimFieldFromBox(mlir::Location loc, mlir::Value box, mlir::Value dim,
-                      int off, mlir::Type ty,
+  loadDimFieldFromBox(mlir::Location loc, mlir::Type boxTy, mlir::Value box,
+                      mlir::Value dim, int off, mlir::Type ty,
                       mlir::ConversionPatternRewriter &rewriter) const {
     assert(box.getType().isa<mlir::LLVM::LLVMPointerType>() &&
            "descriptor inquiry with runtime dim can only be done on descriptor "
            "in memory");
     auto pty = mlir::LLVM::LLVMPointerType::get(ty);
     mlir::LLVM::GEPOp p = genGEP(loc, pty, rewriter, box, 0,
                                  static_cast<int>(kDimsPosInBox), dim, off);
-    return rewriter.create<mlir::LLVM::LoadOp>(loc, ty, p);
+    auto loadOp = rewriter.create<mlir::LLVM::LoadOp>(loc, ty, p);
+    attachTBAATag(loadOp, boxTy, nullptr, p);
+    return loadOp;
   }
 
   mlir::Value
-  getDimFieldFromBox(mlir::Location loc, mlir::Value box, int dim, int off,
-                     mlir::Type ty,
+  getDimFieldFromBox(mlir::Location loc, mlir::Type boxTy, mlir::Value box,
+                     int dim, int off, mlir::Type ty,
                      mlir::ConversionPatternRewriter &rewriter) const {
     if (box.getType().isa<mlir::LLVM::LLVMPointerType>()) {
       auto pty = mlir::LLVM::LLVMPointerType::get(ty);
       mlir::LLVM::GEPOp p = genGEP(loc, pty, rewriter, box, 0,
                                    static_cast<int>(kDimsPosInBox), dim, off);
-      return rewriter.create<mlir::LLVM::LoadOp>(loc, ty, p);
+      auto loadOp = rewriter.create<mlir::LLVM::LoadOp>(loc, ty, p);
+      attachTBAATag(loadOp, boxTy, nullptr, p);
+      return loadOp;
     }
     return rewriter.create<mlir::LLVM::ExtractValueOp>(
         loc, box, llvm::ArrayRef<std::int64_t>{kDimsPosInBox, dim, off});
   }
 
   mlir::Value
-  getStrideFromBox(mlir::Location loc, mlir::Value box, unsigned dim,
+  getStrideFromBox(mlir::Location loc, mlir::Type boxTy, mlir::Value box,
+                   unsigned dim,
                    mlir::ConversionPatternRewriter &rewriter) const {
     auto idxTy = lowerTy().indexType();
-    return getDimFieldFromBox(loc, box, dim, kDimStridePos, idxTy, rewriter);
+    return getDimFieldFromBox(loc, boxTy, box, dim, kDimStridePos, idxTy,
+                              rewriter);
   }
 
   /// Read base address from a fir.box. Returned address has type ty.
   mlir::Value
-  getBaseAddrFromBox(mlir::Location loc, mlir::Type ty, mlir::Value box,
+  getBaseAddrFromBox(mlir::Location loc, mlir::Type resultTy, mlir::Type boxTy,
+                     mlir::Value box,
                      mlir::ConversionPatternRewriter &rewriter) const {
-    return getValueFromBox(loc, box, ty, rewriter, kAddrPosInBox);
+    return getValueFromBox(loc, boxTy, box, resultTy, rewriter, kAddrPosInBox);
   }
 
   mlir::Value
-  getElementSizeFromBox(mlir::Location loc, mlir::Type ty, mlir::Value box,
+  getElementSizeFromBox(mlir::Location loc, mlir::Type resultTy,
+                        mlir::Type boxTy, mlir::Value box,
                         mlir::ConversionPatternRewriter &rewriter) const {
-    return getValueFromBox(loc, box, ty, rewriter, kElemLenPosInBox);
+    return getValueFromBox(loc, boxTy, box, resultTy, rewriter,
+                           kElemLenPosInBox);
   }
 
   // Get the element type given an LLVM type that is of the form
   // [llvm.ptr](array|struct|vector)+ and the provided indexes.
   static mlir::Type getBoxEleTy(mlir::Type type,
                                 llvm::ArrayRef<std::int64_t> indexes) {
     if (auto t = type.dyn_cast<mlir::LLVM::LLVMPointerType>())
       type = t.getElementType();
protected:
   // Return LLVM type of the base address given the LLVM type
   // of the related descriptor (lowered fir.box type).
   static mlir::Type getBaseAddrTypeFromBox(mlir::Type type) {
     return getBoxEleTy(type, {kAddrPosInBox});
   }
 
   /// Read the address of the type descriptor from a box.
   mlir::Value
-  loadTypeDescAddress(mlir::Location loc, mlir::Type ty, mlir::Value box,
+  loadTypeDescAddress(mlir::Location loc, mlir::Type boxTy, mlir::Value box,
                       mlir::ConversionPatternRewriter &rewriter) const {
-    unsigned typeDescFieldId = getTypeDescFieldId(ty);
+    unsigned typeDescFieldId = getTypeDescFieldId(boxTy);
     mlir::Type tdescType = lowerTy().convertTypeDescType(rewriter.getContext());
-    return getValueFromBox(loc, box, tdescType, rewriter, typeDescFieldId);
+    return getValueFromBox(loc, boxTy, box, tdescType, rewriter,
+                           typeDescFieldId);
   }
 
   // Load the attribute from the \p box and perform a check against \p maskValue
   // The final comparison is implemented as `(attribute & maskValue) != 0`.
-  mlir::Value genBoxAttributeCheck(mlir::Location loc, mlir::Value box,
+  mlir::Value genBoxAttributeCheck(mlir::Location loc, mlir::Type boxTy,
+                                   mlir::Value box,
                                    mlir::ConversionPatternRewriter &rewriter,
                                    unsigned maskValue) const {
     mlir::Type attrTy = rewriter.getI32Type();
     mlir::Value attribute =
-        getValueFromBox(loc, box, attrTy, rewriter, kAttributePosInBox);
+        getValueFromBox(loc, boxTy, box, attrTy, rewriter, kAttributePosInBox);
     mlir::LLVM::ConstantOp attrMask =
         genConstantOffset(loc, rewriter, maskValue);
     auto maskRes =
         rewriter.create<mlir::LLVM::AndOp>(loc, attrTy, attribute, attrMask);
     mlir::LLVM::ConstantOp c0 = genConstantOffset(loc, rewriter, 0);
     return rewriter.create<mlir::LLVM::ICmpOp>(
         loc, mlir::LLVM::ICmpPredicate::ne, maskRes, c0);
   }
genAllocaWithType(mlir::Location loc, mlir::Type toTy, unsigned alignment,
     rewriter.restoreInsertionPoint(thisPt);
     return al;
   }
 
   fir::LLVMTypeConverter &lowerTy() const {
     return *static_cast<fir::LLVMTypeConverter *>(this->getTypeConverter());
   }
 
+  void attachTBAATag(mlir::Operation *op, mlir::Type baseFIRType,
+                     mlir::Type accessFIRType, mlir::LLVM::GEPOp gep) const {
+    lowerTy().attachTBAATag(op, baseFIRType, accessFIRType, gep);
+  }
+
   const fir::FIRToLLVMPassOptions &options;
   const BindingTables &bindingTables;
 };
 
 /// FIR conversion pattern template
 template <typename FromOp>
 class FIROpAndTypeConversion : public FIROpConversion<FromOp> {
 public:
struct BoxAddrOpConversion : public FIROpConversion<fir::BoxAddrOp> {
 
   mlir::LogicalResult
   matchAndRewrite(fir::BoxAddrOp boxaddr, OpAdaptor adaptor,
                   mlir::ConversionPatternRewriter &rewriter) const override {
     mlir::Value a = adaptor.getOperands()[0];
     auto loc = boxaddr.getLoc();
     mlir::Type ty = convertType(boxaddr.getType());
     if (auto argty = boxaddr.getVal().getType().dyn_cast<fir::BaseBoxType>()) {
-      rewriter.replaceOp(boxaddr, getBaseAddrFromBox(loc, ty, a, rewriter));
+      rewriter.replaceOp(boxaddr,
+                         getBaseAddrFromBox(loc, ty, argty, a, rewriter));
     } else {
       rewriter.replaceOpWithNewOp<mlir::LLVM::ExtractValueOp>(boxaddr, a, 0);
     }
     return mlir::success();
   }
 };
 
 /// Convert `!fir.boxchar_len` to  `!llvm.extractvalue` for the 2nd part of the
matchAndRewrite(fir::BoxCharLenOp boxCharLen, OpAdaptor adaptor,
     mlir::Value lenAfterCast = integerCast(loc, rewriter, returnValTy, len);
     rewriter.replaceOp(boxCharLen, lenAfterCast);
 
     return mlir::success();
   }
 };
 
 /// Lower `fir.box_dims` to a sequence of operations to extract the requested
-/// dimension infomartion from the boxed value.
+/// dimension information from the boxed value.
 /// Result in a triple set of GEPs and loads.
 struct BoxDimsOpConversion : public FIROpConversion<fir::BoxDimsOp> {
   using FIROpConversion::FIROpConversion;
 
   mlir::LogicalResult
   matchAndRewrite(fir::BoxDimsOp boxdims, OpAdaptor adaptor,
                   mlir::ConversionPatternRewriter &rewriter) const override {
     llvm::SmallVector<mlir::Type, 3> resultTypes = {
         convertType(boxdims.getResult(0).getType()),
         convertType(boxdims.getResult(1).getType()),
         convertType(boxdims.getResult(2).getType()),
     };
-    auto results =
-        getDimsFromBox(boxdims.getLoc(), resultTypes, adaptor.getOperands()[0],
-                       adaptor.getOperands()[1], rewriter);
+    auto results = getDimsFromBox(
+        boxdims.getLoc(), resultTypes, boxdims.getVal().getType(),
+        adaptor.getOperands()[0], adaptor.getOperands()[1], rewriter);
     rewriter.replaceOp(boxdims, results);
     return mlir::success();
   }
 };
 
 /// Lower `fir.box_elesize` to a sequence of operations ro extract the size of
 /// an element in the boxed value.
 struct BoxEleSizeOpConversion : public FIROpConversion<fir::BoxEleSizeOp> {
   using FIROpConversion::FIROpConversion;
 
   mlir::LogicalResult
   matchAndRewrite(fir::BoxEleSizeOp boxelesz, OpAdaptor adaptor,
                   mlir::ConversionPatternRewriter &rewriter) const override {
-    mlir::Value a = adaptor.getOperands()[0];
+    mlir::Value box = adaptor.getOperands()[0];
     auto loc = boxelesz.getLoc();
     auto ty = convertType(boxelesz.getType());
-    auto elemSize = getValueFromBox(loc, a, ty, rewriter, kElemLenPosInBox);
+    auto elemSize = getElementSizeFromBox(loc, ty, boxelesz.getVal().getType(),
+                                          box, rewriter);
     rewriter.replaceOp(boxelesz, elemSize);
     return mlir::success();
   }
 };
 
 /// Lower `fir.box_isalloc` to a sequence of operations to determine if the
 /// boxed value was from an ALLOCATABLE entity.
 struct BoxIsAllocOpConversion : public FIROpConversion<fir::BoxIsAllocOp> {
   using FIROpConversion::FIROpConversion;
 
   mlir::LogicalResult
   matchAndRewrite(fir::BoxIsAllocOp boxisalloc, OpAdaptor adaptor,
                   mlir::ConversionPatternRewriter &rewriter) const override {
     mlir::Value box = adaptor.getOperands()[0];
     auto loc = boxisalloc.getLoc();
-    mlir::Value check =
-        genBoxAttributeCheck(loc, box, rewriter, kAttrAllocatable);
+    mlir::Value check = genBoxAttributeCheck(loc, boxisalloc.getVal().getType(),
+                                             box, rewriter, kAttrAllocatable);
     rewriter.replaceOp(boxisalloc, check);
     return mlir::success();
   }
 };
 
 /// Lower `fir.box_isarray` to a sequence of operations to determine if the
 /// boxed is an array.
 struct BoxIsArrayOpConversion : public FIROpConversion<fir::BoxIsArrayOp> {
   using FIROpConversion::FIROpConversion;
 
   mlir::LogicalResult
   matchAndRewrite(fir::BoxIsArrayOp boxisarray, OpAdaptor adaptor,
                   mlir::ConversionPatternRewriter &rewriter) const override {
     mlir::Value a = adaptor.getOperands()[0];
     auto loc = boxisarray.getLoc();
-    auto rank =
-        getValueFromBox(loc, a, rewriter.getI32Type(), rewriter, kRankPosInBox);
+    auto rank = getValueFromBox(loc, boxisarray.getVal().getType(), a,
+                                rewriter.getI32Type(), rewriter, kRankPosInBox);
     auto c0 = genConstantOffset(loc, rewriter, 0);
     rewriter.replaceOpWithNewOp<mlir::LLVM::ICmpOp>(
         boxisarray, mlir::LLVM::ICmpPredicate::ne, rank, c0);
     return mlir::success();
   }
 };
 
 /// Lower `fir.box_isptr` to a sequence of operations to determined if the
 /// boxed value was from a POINTER entity.
 struct BoxIsPtrOpConversion : public FIROpConversion<fir::BoxIsPtrOp> {
   using FIROpConversion::FIROpConversion;
 
   mlir::LogicalResult
   matchAndRewrite(fir::BoxIsPtrOp boxisptr, OpAdaptor adaptor,
                   mlir::ConversionPatternRewriter &rewriter) const override {
     mlir::Value box = adaptor.getOperands()[0];
     auto loc = boxisptr.getLoc();
-    mlir::Value check = genBoxAttributeCheck(loc, box, rewriter, kAttrPointer);
+    mlir::Value check = genBoxAttributeCheck(loc, boxisptr.getVal().getType(),
+                                             box, rewriter, kAttrPointer);
     rewriter.replaceOp(boxisptr, check);
     return mlir::success();
   }
 };
 
 /// Lower `fir.box_rank` to the sequence of operation to extract the rank from
 /// the box.
 struct BoxRankOpConversion : public FIROpConversion<fir::BoxRankOp> {
   using FIROpConversion::FIROpConversion;
 
   mlir::LogicalResult
   matchAndRewrite(fir::BoxRankOp boxrank, OpAdaptor adaptor,
                   mlir::ConversionPatternRewriter &rewriter) const override {
     mlir::Value a = adaptor.getOperands()[0];
     auto loc = boxrank.getLoc();
     mlir::Type ty = convertType(boxrank.getType());
-    auto result = getValueFromBox(loc, a, ty, rewriter, kRankPosInBox);
+    auto result = getValueFromBox(loc, boxrank.getVal().getType(), a, ty,
+                                  rewriter, kRankPosInBox);
     rewriter.replaceOp(boxrank, result);
     return mlir::success();
   }
 };
 
 /// Lower `fir.boxproc_host` operation. Extracts the host pointer from the
 /// boxproc.
 /// TODO: Part of supporting Fortran 2003 procedure pointers.
struct BoxTypeCodeOpConversion : public FIROpConversion<fir::BoxTypeCodeOp> {
   using FIROpConversion::FIROpConversion;
 
   mlir::LogicalResult
   matchAndRewrite(fir::BoxTypeCodeOp op, OpAdaptor adaptor,
                   mlir::ConversionPatternRewriter &rewriter) const override {
     mlir::Value box = adaptor.getOperands()[0];
     auto loc = box.getLoc();
     auto ty = convertType(op.getType());
-    auto typeCode = getValueFromBox(loc, box, ty, rewriter, kTypePosInBox);
+    auto typeCode = getValueFromBox(loc, op.getBox().getType(), box, ty,
+                                    rewriter, kTypePosInBox);
     rewriter.replaceOp(op, typeCode);
     return mlir::success();
   }
 };
 
 /// Lower `fir.string_lit` to LLVM IR dialect operation.
 struct StringLitOpConversion : public FIROpConversion<fir::StringLitOp> {
   using FIROpConversion::FIROpConversion;
matchAndRewrite(fir::DispatchOp dispatch, OpAdaptor adaptor,
     }
 
     unsigned typeDescFieldId = getTypeDescFieldId(passedObject.getType());
 
     auto descPtr = adaptor.getOperands()[0]
                        .getType()
                        .dyn_cast<mlir::LLVM::LLVMPointerType>();
 
+    // TODO: the following loads from the type descriptor related
+    // data structures must have proper TBAA access tags.
+    // These loads cannot alias with any real data accesses nor
+    // with any box accesses. Moreover, they can probably be marked
+    // as reading from constant memory (fourth operand of a TBAA
+    // tag may be set to true). These accesses probably deserve
+    // separate sub-root in the TBAA graph.
+
     // Load the descriptor.
     auto desc = rewriter.create<mlir::LLVM::LoadOp>(
         loc, descPtr.getElementType(), adaptor.getOperands()[0]);
 
     // Load the type descriptor.
     auto typeDescPtr =
         rewriter.create<mlir::LLVM::ExtractValueOp>(loc, desc, typeDescFieldId);
     auto typeDesc =
consDescriptorPrefix(BOX box, mlir::Type inputType,
     if (sourceBox)
       typeDesc =
           this->loadTypeDescAddress(loc, sourceBoxType, sourceBox, rewriter);
     // When emboxing a fir.ref<none> to an unlimited polymorphic box, get the
     // type code and element size from the box used to extract the type desc.
     if (fir::isUnlimitedPolymorphicType(boxTy) &&
         inputType.isa<mlir::NoneType>() && sourceBox) {
       mlir::Type idxTy = this->lowerTy().indexType();
-      eleSize = this->getElementSizeFromBox(loc, idxTy, sourceBox, rewriter);
-      cfiTy = this->getValueFromBox(loc, sourceBox, cfiTy.getType(), rewriter,
-                                    kTypePosInBox);
+      eleSize =
+          this->getElementSizeFromBox(loc, idxTy, boxTy, sourceBox, rewriter);
+      cfiTy = this->getValueFromBox(loc, boxTy, sourceBox, cfiTy.getType(),
+                                    rewriter, kTypePosInBox);
     }
     auto mod = box->template getParentOfType<mlir::ModuleOp>();
     mlir::Value descriptor = populateDescriptor(
         loc, mod, boxTy, inputType, rewriter, rank, eleSize, cfiTy, typeDesc);
 
     return {boxTy, descriptor, eleSize};
   }
 
consDescriptorPrefix(fir::cg::XReboxOp box, mlir::Value loweredBox,
     auto [eleSize, cfiTy] =
         getSizeAndTypeCode(loc, rewriter, boxTy.getEleTy(), typeparams);
 
     // Reboxing a polymorphic entities. eleSize and type code need to
     // be retrived from the initial box and propagated to the new box.
     if (fir::isPolymorphicType(boxTy) &&
         fir::isPolymorphicType(box.getBox().getType())) {
       mlir::Type idxTy = this->lowerTy().indexType();
-      eleSize = this->getElementSizeFromBox(loc, idxTy, loweredBox, rewriter);
-      cfiTy = this->getValueFromBox(loc, loweredBox, cfiTy.getType(), rewriter,
-                                    kTypePosInBox);
+      eleSize =
+          this->getElementSizeFromBox(loc, idxTy, boxTy, loweredBox, rewriter);
+      cfiTy = this->getValueFromBox(loc, boxTy, loweredBox, cfiTy.getType(),
+                                    rewriter, kTypePosInBox);
       typeDesc = this->loadTypeDescAddress(loc, box.getBox().getType(),
                                            loweredBox, rewriter);
     }
 
     auto mod = box->template getParentOfType<mlir::ModuleOp>();
     mlir::Value descriptor =
         populateDescriptor(loc, mod, boxTy, box.getBox().getType(), rewriter,
                            rank, eleSize, cfiTy, typeDesc);
return thisBlock &&
            mlir::isa<mlir::LLVM::GlobalOp>(thisBlock->getParentOp());
   }
 
   /// If the embox is not in a globalOp body, allocate storage for the box;
   /// store the value inside and return the generated alloca. Return the input
   /// value otherwise.
   mlir::Value
   placeInMemoryIfNotGlobalInit(mlir::ConversionPatternRewriter &rewriter,
-                               mlir::Location loc, mlir::Value boxValue) const {
+                               mlir::Location loc, mlir::Type boxTy,
+                               mlir::Value boxValue) const {
     if (isInGlobalOp(rewriter))
       return boxValue;
     auto boxPtrTy = mlir::LLVM::LLVMPointerType::get(boxValue.getType());
     auto alloca =
         this->genAllocaWithType(loc, boxPtrTy, defaultAlign, rewriter);
-    rewriter.create<mlir::LLVM::StoreOp>(loc, boxValue, alloca);
+    auto storeOp = rewriter.create<mlir::LLVM::StoreOp>(loc, boxValue, alloca);
+    this->attachTBAATag(storeOp, boxTy, boxTy, nullptr);
     return alloca;
   }
 };
 
 /// Compute the extent of a triplet slice (lb:ub:step).
 static mlir::Value
 computeTripletExtent(mlir::ConversionPatternRewriter &rewriter,
                      mlir::Location loc, mlir::Value lb, mlir::Value ub,
auto [boxTy, dest, eleSize] = consDescriptorPrefix(
         /*rank=*/0, /*lenParams=*/operands.drop_front(1), sourceBox,
         sourceBoxType);
     dest = insertBaseAddress(rewriter, embox.getLoc(), dest, operands[0]);
     if (isDerivedTypeWithLenParams(boxTy)) {
       TODO(embox.getLoc(),
            "fir.embox codegen of derived with length parameters");
       return mlir::failure();
     }
-    auto result = placeInMemoryIfNotGlobalInit(rewriter, embox.getLoc(), dest);
+    auto result =
+        placeInMemoryIfNotGlobalInit(rewriter, embox.getLoc(), boxTy, dest);
     rewriter.replaceOp(embox, result);
     return mlir::success();
   }
 };
 
 /// Create a generic box on a memory reference.
 struct XEmboxOpConversion : public EmboxCommonConversion<fir::cg::XEmboxOp> {
   using EmboxCommonConversion::EmboxCommonConversion;
if (hasSlice || hasSubcomp || hasSubstr) {
         substringOffset = operands[xbox.substrOffset()];
       base = genBoxOffsetGep(rewriter, loc, base, ptrOffset, cstInteriorIndices,
                              fieldIndices, substringOffset);
     }
     dest = insertBaseAddress(rewriter, loc, dest, base);
     if (isDerivedTypeWithLenParams(boxTy))
       TODO(loc, "fir.embox codegen of derived with length parameters");
 
-    mlir::Value result = placeInMemoryIfNotGlobalInit(rewriter, loc, dest);
+    mlir::Value result =
+        placeInMemoryIfNotGlobalInit(rewriter, loc, boxTy, dest);
     rewriter.replaceOp(xbox, result);
     return mlir::success();
   }
 
   /// Return true if `xbox` has a normalized lower bounds attribute. A box value
   /// that is neither a POINTER nor an ALLOCATABLE should be normalized to a
   /// zero origin lower bound for interoperability with BIND(C).
   inline static bool normalizedLowerBound(fir::cg::XEmboxOp xbox) {
if (isInGlobalOp(rewriter))
       if (auto unrealizedCast =
               loweredBox.getDefiningOp<mlir::UnrealizedConversionCastOp>())
         loweredBox = unrealizedCast.getInputs()[0];
 
     // Create new descriptor and fill its non-shape related data.
     llvm::SmallVector<mlir::Value, 2> lenParams;
     mlir::Type inputEleTy = getInputEleTy(rebox);
     if (auto charTy = inputEleTy.dyn_cast<fir::CharacterType>()) {
-      mlir::Value len = getElementSizeFromBox(loc, idxTy, loweredBox, rewriter);
+      mlir::Value len = getElementSizeFromBox(
+          loc, idxTy, rebox.getBox().getType(), loweredBox, rewriter);
       if (charTy.getFKind() != 1) {
         mlir::Value width =
             genConstantIndex(loc, idxTy, rewriter, charTy.getFKind());
         len = rewriter.create<mlir::LLVM::SDivOp>(loc, idxTy, len, width);
       }
       lenParams.emplace_back(len);
     } else if (auto recTy = inputEleTy.dyn_cast<fir::RecordType>()) {
       if (recTy.getNumLenParams() != 0)
auto [boxTy, dest, eleSize] =
                              lenParams, typeDescAddr);
 
     // Read input extents, strides, and base address
     llvm::SmallVector<mlir::Value> inputExtents;
     llvm::SmallVector<mlir::Value> inputStrides;
     const unsigned inputRank = rebox.getRank();
     for (unsigned dim = 0; dim < inputRank; ++dim) {
       llvm::SmallVector<mlir::Value, 3> dimInfo =
-          getDimsFromBox(loc, {idxTy, idxTy, idxTy}, loweredBox, dim, rewriter);
+          getDimsFromBox(loc, {idxTy, idxTy, idxTy}, rebox.getBox().getType(),
+                         loweredBox, dim, rewriter);
       inputExtents.emplace_back(dimInfo[1]);
       inputStrides.emplace_back(dimInfo[2]);
     }
 
     mlir::Type baseTy = getBaseAddrTypeFromBox(loweredBox.getType());
-    mlir::Value baseAddr =
-        getBaseAddrFromBox(loc, baseTy, loweredBox, rewriter);
+    mlir::Value baseAddr = getBaseAddrFromBox(
+        loc, baseTy, rebox.getBox().getType(), loweredBox, rewriter);
 
     if (!rebox.getSlice().empty() || !rebox.getSubcomponent().empty())
-      return sliceBox(rebox, dest, baseAddr, inputExtents, inputStrides,
+      return sliceBox(rebox, boxTy, dest, baseAddr, inputExtents, inputStrides,
                       operands, rewriter);
-    return reshapeBox(rebox, dest, baseAddr, inputExtents, inputStrides,
+    return reshapeBox(rebox, boxTy, dest, baseAddr, inputExtents, inputStrides,
                       operands, rewriter);
   }
 
 private:
   /// Write resulting shape and base address in descriptor, and replace rebox
   /// op.
   mlir::LogicalResult
-  finalizeRebox(fir::cg::XReboxOp rebox, mlir::Value dest, mlir::Value base,
-                mlir::ValueRange lbounds, mlir::ValueRange extents,
-                mlir::ValueRange strides,
+  finalizeRebox(fir::cg::XReboxOp rebox, mlir::Type destBoxTy, mlir::Value dest,
+                mlir::Value base, mlir::ValueRange lbounds,
+                mlir::ValueRange extents, mlir::ValueRange strides,
                 mlir::ConversionPatternRewriter &rewriter) const {
     mlir::Location loc = rebox.getLoc();
     mlir::Value zero =
         genConstantIndex(loc, lowerTy().indexType(), rewriter, 0);
     mlir::Value one = genConstantIndex(loc, lowerTy().indexType(), rewriter, 1);
     for (auto iter : llvm::enumerate(llvm::zip(extents, strides))) {
       mlir::Value extent = std::get<0>(iter.value());
       unsigned dim = iter.index();
       mlir::Value lb = one;
       if (!lbounds.empty()) {
         lb = lbounds[dim];
         auto extentIsEmpty = rewriter.create<mlir::LLVM::ICmpOp>(
             loc, mlir::LLVM::ICmpPredicate::eq, extent, zero);
         lb = rewriter.create<mlir::LLVM::SelectOp>(loc, extentIsEmpty, one, lb);
       };
       dest = insertLowerBound(rewriter, loc, dest, dim, lb);
       dest = insertExtent(rewriter, loc, dest, dim, extent);
       dest = insertStride(rewriter, loc, dest, dim, std::get<1>(iter.value()));
     }
     dest = insertBaseAddress(rewriter, loc, dest, base);
     mlir::Value result =
-        placeInMemoryIfNotGlobalInit(rewriter, rebox.getLoc(), dest);
+        placeInMemoryIfNotGlobalInit(rewriter, rebox.getLoc(), destBoxTy, dest);
     rewriter.replaceOp(rebox, result);
     return mlir::success();
   }
 
   // Apply slice given the base address, extents and strides of the input box.
   mlir::LogicalResult
-  sliceBox(fir::cg::XReboxOp rebox, mlir::Value dest, mlir::Value base,
-           mlir::ValueRange inputExtents, mlir::ValueRange inputStrides,
-           mlir::ValueRange operands,
+  sliceBox(fir::cg::XReboxOp rebox, mlir::Type destBoxTy, mlir::Value dest,
+           mlir::Value base, mlir::ValueRange inputExtents,
+           mlir::ValueRange inputStrides, mlir::ValueRange operands,
            mlir::ConversionPatternRewriter &rewriter) const {
     mlir::Location loc = rebox.getLoc();
     mlir::Type voidPtrTy = ::getVoidPtrType(rebox.getContext());
     mlir::Type idxTy = lowerTy().indexType();
     mlir::Value zero = genConstantIndex(loc, idxTy, rewriter, 0);
     // Apply subcomponent and substring shift on base address.
     if (!rebox.getSubcomponent().empty() || !rebox.getSubstr().empty()) {
       // Cast to inputEleTy* so that a GEP can be used.
if (!rebox.getSubcomponent().empty() || !rebox.getSubstr().empty()) {
       base = genBoxOffsetGep(rewriter, loc, base, zero,
                              /*cstInteriorIndices=*/std::nullopt, fieldIndices,
                              substringOffset);
     }
 
     if (rebox.getSlice().empty())
       // The array section is of the form array[%component][substring], keep
       // the input array extents and strides.
-      return finalizeRebox(rebox, dest, base, /*lbounds*/ std::nullopt,
-                           inputExtents, inputStrides, rewriter);
+      return finalizeRebox(rebox, destBoxTy, dest, base,
+                           /*lbounds*/ std::nullopt, inputExtents, inputStrides,
+                           rewriter);
 
     // Strides from the fir.box are in bytes.
     base = rewriter.create<mlir::LLVM::BitcastOp>(loc, voidPtrTy, base);
 
     // The slice is of the form array(i:j:k)[%component]. Compute new extents
     // and strides.
     llvm::SmallVector<mlir::Value> slicedExtents;
     llvm::SmallVector<mlir::Value> slicedStrides;
for (unsigned i = 0; i < inputRank;
                                                   sliceUb, step, zero, idxTy);
         slicedExtents.emplace_back(extent);
         // stride = step*input_stride
         mlir::Value stride =
             rewriter.create<mlir::LLVM::MulOp>(loc, idxTy, step, inputStride);
         slicedStrides.emplace_back(stride);
       }
     }
-    return finalizeRebox(rebox, dest, base, /*lbounds*/ std::nullopt,
+    return finalizeRebox(rebox, destBoxTy, dest, base, /*lbounds*/ std::nullopt,
                          slicedExtents, slicedStrides, rewriter);
   }
 
   /// Apply a new shape to the data described by a box given the base address,
   /// extents and strides of the box.
   mlir::LogicalResult
-  reshapeBox(fir::cg::XReboxOp rebox, mlir::Value dest, mlir::Value base,
-             mlir::ValueRange inputExtents, mlir::ValueRange inputStrides,
-             mlir::ValueRange operands,
+  reshapeBox(fir::cg::XReboxOp rebox, mlir::Type destBoxTy, mlir::Value dest,
+             mlir::Value base, mlir::ValueRange inputExtents,
+             mlir::ValueRange inputStrides, mlir::ValueRange operands,
              mlir::ConversionPatternRewriter &rewriter) const {
     mlir::ValueRange reboxShifts{operands.begin() + rebox.shiftOffset(),
                                  operands.begin() + rebox.shiftOffset() +
                                      rebox.getShift().size()};
     if (rebox.getShape().empty()) {
       // Only setting new lower bounds.
-      return finalizeRebox(rebox, dest, base, reboxShifts, inputExtents,
-                           inputStrides, rewriter);
+      return finalizeRebox(rebox, destBoxTy, dest, base, reboxShifts,
+                           inputExtents, inputStrides, rewriter);
     }
 
     mlir::Location loc = rebox.getLoc();
     // Strides from the fir.box are in bytes.
     mlir::Type voidPtrTy = ::getVoidPtrType(rebox.getContext());
     base = rewriter.create<mlir::LLVM::BitcastOp>(loc, voidPtrTy, base);
 
     llvm::SmallVector<mlir::Value> newStrides;
reshapeBox(fir::cg::XReboxOp rebox, mlir::Type destBoxTy, mlir::Value dest,
     for (unsigned i = 0; i < rebox.getShape().size(); ++i) {
       mlir::Value rawExtent = operands[rebox.shapeOffset() + i];
       mlir::Value extent = integerCast(loc, rewriter, idxTy, rawExtent);
       newExtents.emplace_back(extent);
       newStrides.emplace_back(stride);
       // nextStride = extent * stride;
       stride = rewriter.create<mlir::LLVM::MulOp>(loc, idxTy, extent, stride);
     }
-    return finalizeRebox(rebox, dest, base, reboxShifts, newExtents, newStrides,
-                         rewriter);
+    return finalizeRebox(rebox, destBoxTy, dest, base, reboxShifts, newExtents,
+                         newStrides, rewriter);
   }
 
   /// Return scalar element type of the input box.
   static mlir::Type getInputEleTy(fir::cg::XReboxOp rebox) {
     auto ty = fir::dyn_cast_ptrOrBoxEleTy(rebox.getBox().getType());
     if (auto seqTy = ty.dyn_cast<fir::SequenceType>())
       return seqTy.getEleTy();
     return ty;
for (unsigned i = 0; i < rank; ++i, ++indexOffset, ++shapeOffset,
             integerCast(loc, rewriter, idxTy, operands[sliceOffset]);
         auto adj = rewriter.create<mlir::LLVM::SubOp>(loc, idxTy, sliceLb, lb);
         diff = rewriter.create<mlir::LLVM::AddOp>(loc, idxTy, diff, adj);
       }
       // Update the offset given the stride and the zero based index `diff`
       // that was just computed.
       if (baseIsBoxed) {
         // Use stride in bytes from the descriptor.
-        mlir::Value stride = getStrideFromBox(loc, operands[0], i, rewriter);
+        mlir::Value stride = getStrideFromBox(loc, coor.getMemref().getType(),
+                                              operands[0], i, rewriter);
         auto sc = rewriter.create<mlir::LLVM::MulOp>(loc, idxTy, diff, stride);
         offset = rewriter.create<mlir::LLVM::AddOp>(loc, idxTy, sc, offset);
       } else {
         // Use stride computed at last iteration.
         auto sc = rewriter.create<mlir::LLVM::MulOp>(loc, idxTy, diff, prevExt);
         offset = rewriter.create<mlir::LLVM::AddOp>(loc, idxTy, sc, offset);
         // Compute next stride assuming contiguity of the base array
         // (in element number).
         auto nextExt = integerCast(loc, rewriter, idxTy, operands[shapeOffset]);
         prevExt =
             rewriter.create<mlir::LLVM::MulOp>(loc, idxTy, prevExt, nextExt);
       }
     }
 
     // Add computed offset to the base address.
     if (baseIsBoxed) {
       // Working with byte offsets. The base address is read from the fir.box.
       // and need to be casted to i8* to do the pointer arithmetic.
       mlir::Type baseTy = getBaseAddrTypeFromBox(operands[0].getType());
-      mlir::Value base = getBaseAddrFromBox(loc, baseTy, operands[0], rewriter);
+      mlir::Value base = getBaseAddrFromBox(
+          loc, baseTy, coor.getMemref().getType(), operands[0], rewriter);
       mlir::Type voidPtrTy = getVoidPtrType();
       base = rewriter.create<mlir::LLVM::BitcastOp>(loc, voidPtrTy, base);
       llvm::SmallVector<mlir::LLVM::GEPArg> args{offset};
       auto addr =
           rewriter.create<mlir::LLVM::GEPOp>(loc, voidPtrTy, base, args);
       if (coor.getSubcomponent().empty()) {
         rewriter.replaceOpWithNewOp<mlir::LLVM::BitcastOp>(coor, ty, addr);
         return mlir::success();
doRewriteBox(fir::CoordinateOp coor, mlir::Type ty, mlir::ValueRange operands,
     // 2.3 (`fir.derived` inside `fir.array`)
     //   %box = ... : !fir.box<!fir.array<10 x !fir.type<derived_1{field_1:f32,
     //   field_2:f32}>>> %idx1 = ... : index %idx2 = ... : i32 %resultAddr =
     //   coordinate_of %box, %idx1, %idx2 : !fir.ref<f32>
     // 2.4. TODO: Either document or disable any other case that the following
     //  implementation might convert.
     mlir::Value resultAddr =
         getBaseAddrFromBox(loc, getBaseAddrTypeFromBox(boxBaseAddr.getType()),
-                           boxBaseAddr, rewriter);
+                           boxObjTy, boxBaseAddr, rewriter);
     // Component Type
     auto cpnTy = fir::dyn_cast_ptrOrBoxEleTy(boxObjTy);
     mlir::Type voidPtrTy = ::getVoidPtrType(coor.getContext());
 
     for (unsigned i = 1, last = operands.size(); i < last; ++i) {
       if (auto arrTy = cpnTy.dyn_cast<fir::SequenceType>()) {
         if (i != 1)
           TODO(loc, "fir.array nested inside other array and/or derived type");
         // Applies byte strides from the box. Ignore lower bound from box
         // since fir.coordinate_of indexes are zero based. Lowering takes care
         // of lower bound aspects. This both accounts for dynamically sized
         // types and non contiguous arrays.
         auto idxTy = lowerTy().indexType();
         mlir::Value off = genConstantIndex(loc, idxTy, rewriter, 0);
         for (unsigned index = i, lastIndex = i + arrTy.getDimension();
              index < lastIndex; ++index) {
           mlir::Value stride =
-              getStrideFromBox(loc, operands[0], index - i, rewriter);
+              getStrideFromBox(loc, boxObjTy, operands[0], index - i, rewriter);
           auto sc = rewriter.create<mlir::LLVM::MulOp>(loc, idxTy,
                                                        operands[index], stride);
           off = rewriter.create<mlir::LLVM::AddOp>(loc, idxTy, sc, off);
         }
         auto voidPtrBase =
             rewriter.create<mlir::LLVM::BitcastOp>(loc, voidPtrTy, resultAddr);
         resultAddr = rewriter.create<mlir::LLVM::GEPOp>(
             loc, voidPtrTy, voidPtrBase,
if (auto boxTy = load.getType().dyn_cast<fir::BaseBoxType>()) {
       // size that is know at compile time. The copy needs to be runtime driven
       // depending on the actual dynamic rank or type.
       if (seqTy && seqTy.hasUnknownShape())
         TODO(loc, "loading or assumed rank fir.box");
       mlir::Type boxPtrTy = inputBoxStorage.getType();
       auto boxValue = rewriter.create<mlir::LLVM::LoadOp>(
           loc, boxPtrTy.cast<mlir::LLVM::LLVMPointerType>().getElementType(),
           inputBoxStorage);
+      attachTBAATag(boxValue, boxTy, boxTy, nullptr);
       auto newBoxStorage =
           genAllocaWithType(loc, boxPtrTy, defaultAlign, rewriter);
+      auto storeOp =
           rewriter.create<mlir::LLVM::StoreOp>(loc, boxValue, newBoxStorage);
+      attachTBAATag(storeOp, boxTy, boxTy, nullptr);
       rewriter.replaceOp(load, newBoxStorage.getResult());
     } else {
-      rewriter.replaceOpWithNewOp<mlir::LLVM::LoadOp>(
-          load, convertType(load.getType()), adaptor.getOperands(),
-          load->getAttrs());
+      mlir::Type loadTy = convertType(load.getType());
+      auto loadOp = rewriter.create<mlir::LLVM::LoadOp>(
+          load.getLoc(), loadTy, adaptor.getOperands(), load->getAttrs());
+      attachTBAATag(loadOp, load.getType(), load.getType(), nullptr);
+      rewriter.replaceOp(load, loadOp.getResult());
     }
     return mlir::success();
   }
 };
 
 /// Lower `fir.no_reassoc` to LLVM IR dialect.
 /// TODO: how do we want to enforce this in LLVM-IR? Can we manipulate the fast
 /// math flags?

 
 /// `fir.store` --> `llvm.store`
 struct StoreOpConversion : public FIROpConversion<fir::StoreOp> {
   using FIROpConversion::FIROpConversion;
 
   mlir::LogicalResult
   matchAndRewrite(fir::StoreOp store, OpAdaptor adaptor,
                   mlir::ConversionPatternRewriter &rewriter) const override {
-    if (store.getValue().getType().isa<fir::BaseBoxType>()) {
-      // fir.box value is actually in memory, load it first before storing it.
-      mlir::Location loc = store.getLoc();
+    mlir::Type storeTy = store.getValue().getType();
+    mlir::LLVM::StoreOp newStoreOp;
+    if (auto boxTy = storeTy.dyn_cast<fir::BaseBoxType>()) {
+      // fir.box value is actually in memory, load it first before storing it.
       mlir::Type boxPtrTy = adaptor.getOperands()[0].getType();
       auto val = rewriter.create<mlir::LLVM::LoadOp>(
           loc, boxPtrTy.cast<mlir::LLVM::LLVMPointerType>().getElementType(),
           adaptor.getOperands()[0]);
-      rewriter.replaceOpWithNewOp<mlir::LLVM::StoreOp>(
-          store, val, adaptor.getOperands()[1]);
+      attachTBAATag(val, boxTy, boxTy, nullptr);
+      newStoreOp = rewriter.create<mlir::LLVM::StoreOp>(
+          loc, val, adaptor.getOperands()[1]);
     } else {
-      rewriter.replaceOpWithNewOp<mlir::LLVM::StoreOp>(
-          store, adaptor.getOperands()[0], adaptor.getOperands()[1]);
+      newStoreOp = rewriter.create<mlir::LLVM::StoreOp>(
+          loc, adaptor.getOperands()[0], adaptor.getOperands()[1]);
     }
+    attachTBAATag(newStoreOp, storeTy, storeTy, nullptr);
+    rewriter.eraseOp(store);
     return mlir::success();
   }
 };
 
 namespace {
 
 /// Convert `fir.unboxchar` into two `llvm.extractvalue` instructions. One for
 /// the character buffer and one for the buffer length.
for (auto dispatchTableOp : mod.getOps<fir::DispatchTableOp>()) {
       for (auto dtEntry : dispatchTableOp.getBlock().getOps<fir::DTEntryOp>()) {
         bindings[dtEntry.getMethod()] = bindingIdx;
         ++bindingIdx;
       }
       bindingTables[dispatchTableOp.getSymName()] = bindings;
     }
 
     auto *context = getModule().getContext();
-    fir::LLVMTypeConverter typeConverter{getModule()};
+    fir::LLVMTypeConverter typeConverter{getModule(),
+                                         options.applyTBAA || applyTBAA};
     mlir::RewritePatternSet pattern(context);
     pattern.insert<
         AbsentOpConversion, AddcOpConversion, AddrOfOpConversion,
         AllocaOpConversion, AllocMemOpConversion, BoxAddrOpConversion,
         BoxCharLenOpConversion, BoxDimsOpConversion, BoxEleSizeOpConversion,
         BoxIsAllocOpConversion, BoxIsArrayOpConversion, BoxIsPtrOpConversion,
         BoxProcHostOpConversion, BoxRankOpConversion, BoxTypeCodeOpConversion,
         BoxTypeDescOpConversion, CallOpConversion, CmpcOpConversion,

flang/lib/Optimizer/CodeGen/DescriptorModel.h

 //===----------------------------------------------------------------------===//
 
 #ifndef OPTIMIZER_DESCRIPTOR_MODEL_H
 #define OPTIMIZER_DESCRIPTOR_MODEL_H
 
 #include "flang/ISO_Fortran_binding.h"
 #include "flang/Runtime/descriptor.h"
 #include "mlir/Dialect/LLVMIR/LLVMTypes.h"
+#include "mlir/IR/BuiltinTypes.h"
 #include "llvm/Support/ErrorHandling.h"
 #include <tuple>
 
 namespace fir {
 
 using TypeBuilderFunc = mlir::Type (*)(mlir::MLIRContext *);
 
 /// Get the LLVM IR dialect model for building a particular C++ type, `T`.

flang/lib/Optimizer/CodeGen/TBAABuilder.h

+//===-- TBAABuilder.h -- TBAA builder declarations --------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Coding style: https://mlir.llvm.org/getting_started/DeveloperGuide/
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef FORTRAN_OPTIMIZER_CODEGEN_TBAABUILDER_H
+#define FORTRAN_OPTIMIZER_CODEGEN_TBAABUILDER_H
+
+#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
+#include "mlir/IR/BuiltinAttributes.h"
+
+namespace fir {
+
+// TBAA builder provides mapping between FIR types and their TBAA type
+// descriptors, and methods to populate that mapping during FIR to LLVM
+// types conversion and to attach llvm.tbaa attributes to memory accessing
+// instructions.
+//
+// TBAA type information is represented with LLVM::MetadataOp operation
+// with specific symbol name `TBAABuilder::tbaaMetaOpName`. The basic
+// TBAA tree used for Flang consists of the following nodes:
+//   llvm.metadata @__flang_tbaa {
+//     llvm.tbaa_root @root_0 {id = "Flang Type TBAA Root"}
+//     llvm.tbaa_type_desc @type_desc_1 {id = "any access",
+//                                       members = {<@root_0, 0>}}
+//     llvm.tbaa_type_desc @type_desc_2 {id = "any data access",
+//                                       members = {<@type_desc_1, 0>}}
+//     llvm.tbaa_type_desc @type_desc_3 {id = "descriptor member",
+//                                       members = {<@type_desc_1, 0>}}
+//   }
+//
+// The `<any data access>` and `<descriptor member>` type descriptors
+// are two sub-roots of the basic TBAA tree, and they allow representing
+// box and non-box accesses, which can never alias in the current Flang
+// implementation. The `<any access>` type descriptor is their common parrent
+// that can be used for representing accesses that may alias box and non-box
+// accesses if an access cannot be classified strictly as box or non-box.
+// In the current implementation `<any access>` is not used by TBAA access tags,
+// because it is always known whether operation accesses box or non-box.
+//
+// Given this basic TBAA tree structure, the box/descriptor types may
+// be represented like this:
+//   llvm.tbaa_type_desc @type_desc_4 {
+//       id = "CFI_cdesc_t_dim0",
+//       members = {<@type_desc_3, 0>, // base_addr
+//                  <@type_desc_3, 8>, // elem_len
+//                  <@type_desc_3, 16>, // version
+//                  <@type_desc_3, 20>, // rank
+//                  <@type_desc_3, 21>, // type
+//                  <@type_desc_3, 22>, // attribute
+//                  <@type_desc_3, 23>} // f18Addendum
+//   }
+//   llvm.tbaa_type_desc @type_desc_5 {
+//       id = "CFI_cdesc_t_dim1",
+//       members = {<@type_desc_3, 0>, // base_addr
+//                  <@type_desc_3, 8>, // elem_len
+//                  <@type_desc_3, 16>, // version
+//                  <@type_desc_3, 20>, // rank
+//                  <@type_desc_3, 21>, // type
+//                  <@type_desc_3, 22>, // attribute
+//                  <@type_desc_3, 23>, // f18Addendum
+//                  <@type_desc_3, 24>, // dim[0].lower_bound
+//                  <@type_desc_3, 32>, // dim[0].extent
+//                  <@type_desc_3, 40>} // dim[0].sm
+//   }
+//   llvm.tbaa_type_desc @type_desc_6 {
+//       id = "CFI_cdesc_t_dim2",
+//       members = {<@type_desc_3, 0>, // base_addr
+//                  <@type_desc_3, 8>, // elem_len
+//                  <@type_desc_3, 16>, // version
+//                  <@type_desc_3, 20>, // rank
+//                  <@type_desc_3, 21>, // type
+//                  <@type_desc_3, 22>, // attribute
+//                  <@type_desc_3, 23>, // f18Addendum
+//                  <@type_desc_3, 24>, // dim[0].lower_bound
+//                  <@type_desc_3, 32>, // dim[0].extent
+//                  <@type_desc_3, 40>, // dim[0].sm
+//                  <@type_desc_3, 48>, // dim[1].lower_bound
+//                  <@type_desc_3, 56>, // dim[1].extent
+//                  <@type_desc_3, 64>} // dim[1].sm
+//   }
+// etc.
+//
+// Note that the TBAA type descriptors cannot represent array members
+// of structures, so the `dim` array in the descriptor structure
+// has to be represented as linear set of members.
+//
+// We can use the same TBAA type descriptor for all members of the F18
+// descriptor structure, because the actual accesses of the F18 descriptor
+// members will be disambiguated based on their offset off the beginning
+// of the descriptor. Thus, all members have the same `<descriptor member>`
+// type in the TBAA graph.
+//
+// The TBAA type descriptors have to be created during FIR to LLVM type
+// conversion, so fir::LLVMTypeConverter have to provide the member offsets
+// to TBAABuilder - the offsets must be computed based on the LLVM type
+// to which the FIR type is being converted.
+//
+// TBAABuilder keeps a map between the FIR type and its TBAA type descriptor.
+// The map is used when a TBAA tag needs to be attached to a memory accessing
+// operation given the FIR types identifying the access' base and access type
+// and the offset within the base type, e.g. an access of one dimensional
+// descriptor's `base_addr` member may be defined by:
+//   * base FIR type: !fir.box<!fir.array<?xf32>> - the resulting
+//     access tag will use `<CFI_cdesc_t_dim1>` type descriptor for the base
+//     type.
+//   * access FIR type: <undefined> - all accesses within descriptors
+//     are always represented with `<descriptor member>` type descriptor.
+//   * offset:
+//       llvm.getelementptr %arg0[0, 0] :
+//           (!llvm.ptr<struct<(ptr<f32>, i64, i32, i8, i8, i8, i8,
+//                              array<1 x array<3 x i64>>)>>) ->
+//           !llvm.ptr<ptr<f32>>
+//     The offset is computed based on the LLVM::GEPOp's indices and the LLVM
+//     type layout.
+//
+// Detailed representation of the layout of the F18 descriptors is required
+// to disambiguate accesses of the different members of the descriptors,
+// e.g. a read of `base_addr` member (of one box) can never alias with
+// a write of `rank` member (of another box).
+//
+// TODO: define handling of assumed-rank arrays' boxes (they can always
+// be represented with a conservative tag:
+//   < `<descriptor member>`, `<descriptor member>`, 0 >
+// so that they alias with any other box accesses.
+//
+// The same representation can be used for user-defined types, though,
+// strict type aliasing cannot be applied for Fortran programs without
+// additional guarantees from the user. Fortran's storage association
+// constructs provide a way to alias data of different types, so using
+// TBAA would be incorrect, e.g.:
+//   subroutine test()
+//     real :: a
+//     integer :: b
+//     equivalence (a, b)
+//     a = 1.0
+//     call test2(b)
+//   end subroutine test
+//
+// The store operation for `a = 1.0` has the base/access type `f32`,
+// while a load from `b` inside `test2` will have base/access type
+// `i32`. Due to the storage association the store and the load alias,
+// so using the access types to create TBAA access tags may result
+// in incorrect result if `test2` was inlined. Moreover, in scope
+// of `test2` Flang is not able to indentify whether `b` is part
+// of an equivalence.
+//
+// TBAA may still be applied for programs not using storage association
+// for objects of different data types (e.g. under opt-in compiler option).
+//
+// The initial implementation does not create detailed type descriptors
+// for box types and always uses the conservative box access tag:
+//   < `<descriptor member>`, `<descriptor member>`, 0 >
+//
+// Given the storage association, all non-box accesses are represented
+// with the conservative data access tag:
+//   < `<any data access>`, `<any data access>`, 0 >
+class TBAABuilder {
+public:
+  TBAABuilder(mlir::ModuleOp module, bool applyTBAA);
+  TBAABuilder(TBAABuilder const &) = delete;
+  TBAABuilder &operator=(TBAABuilder const &) = delete;
+
+  // Attach llvm.tbaa attribute to the given memory accessing operation
+  // based on the provided base/access FIR types and the GEPOp.
+  void attachTBAATag(mlir::Operation *op, mlir::Type baseFIRType,
+                     mlir::Type accessFIRType, mlir::LLVM::GEPOp gep);
+
+private:
+  // Return unique string name based on `basename`.
+  std::string getNewTBAANodeName(llvm::StringRef basename);
+
+  // Find or create TBAATagOp operation (TBAA access tag) with the specified
+  // components and return the symbol it defines.
+  mlir::SymbolRefAttr getAccessTag(mlir::SymbolRefAttr baseTypeDesc,
+                                   mlir::SymbolRefAttr accessTypeDesc,
+                                   int64_t offset);
+  // Returns symbol of TBAATagOp representing access tag:
+  //   < <descriptor member>, <descriptor member>, 0 >
+  mlir::SymbolRefAttr getAnyBoxAccessTag();
+  // Returns symbol of TBAATagOp representing access tag:
+  //   < <any data access>, <any data access>, 0 >
+  mlir::SymbolRefAttr getAnyDataAccessTag();
+
+  // Returns symbol of TBAATagOp representing access tag
+  // described by the base and access FIR types and the LLVM::GepOp
+  // representing the access in terms of the FIR types converted
+  // to LLVM types. The base type must be derivative of fir::BaseBoxType.
+  mlir::SymbolRefAttr getBoxAccessTag(mlir::Type baseFIRType,
+                                      mlir::Type accessFIRType,
+                                      mlir::LLVM::GEPOp gep);
+
+  // Returns symbol of TBAATagOp representing access tag
+  // described by the base and access FIR types and the LLVM::GepOp
+  // representing the access in terms of the FIR types converted
+  // to LLVM types. The FIR types must describe the "data" access,
+  // i.e. not an access of any box/descriptor member.
+  mlir::SymbolRefAttr getDataAccessTag(mlir::Type baseFIRType,
+                                       mlir::Type accessFIRType,
+                                       mlir::LLVM::GEPOp gep);
+
+  // Set to true, if TBAA builder is active, otherwise, all public
+  // methods are no-ops.
+  bool enableTBAA;
+
+  // LLVM::MetadataOp holding the TBAA operations.
+  mlir::LLVM::MetadataOp tbaaMetaOp;
+  // Symbol name of tbaaMetaOp.
+  static constexpr llvm::StringRef tbaaMetaOpName = "__flang_tbaa";
+
+  // Base names for TBAA operations:
+  //   TBAARootMetadataOp:
+  static constexpr llvm::StringRef kRootSymBasename = "root";
+  //   TBAATypeDescriptorOp:
+  static constexpr llvm::StringRef kTypeDescSymBasename = "type_desc";
+  //   TBAATagOp:
+  static constexpr llvm::StringRef kTagSymBasename = "tag";
+
+  // Symbol defined by the LLVM::TBAARootMetadataOp identifying
+  // Flang's TBAA root.
+  mlir::SymbolRefAttr flangTBAARoot;
+  // Identity string for Flang's TBAA root.
+  static constexpr llvm::StringRef flangTBAARootId = "Flang Type TBAA Root";
+
+  // Symbol defined by LLVM::TBAATypeDescriptorOp identifying
+  // "any access".
+  mlir::SymbolRefAttr anyAccessTypeDesc;
+  // Identity string for "any access" type descriptor.
+  static constexpr llvm::StringRef anyAccessTypeDescId = "any access";
+
+  // Symbol defined by LLVM::TBAATypeDescriptorOp identifying
+  // "any data access" (i.e. non-box memory access).
+  mlir::SymbolRefAttr anyDataAccessTypeDesc;
+  // Identity string for "any data access" type descriptor.
+  static constexpr llvm::StringRef anyDataAccessTypeDescId = "any data access";
+
+  // Symbol defined by LLVM::TBAATypeDescriptorOp identifying
+  // "descriptor member" access, i.e. any access within the bounds
+  // of a box/descriptor.
+  mlir::SymbolRefAttr boxMemberTypeDesc;
+  // Identity string for "descriptor member" type descriptor.
+  static constexpr llvm::StringRef boxMemberTypeDescId = "descriptor member";
+
+  // Counter for unique naming of TBAA operations' symbols.
+  unsigned tbaaNodeCounter = 0;
+
+  // Mapping from a FIR type to the symbol defined by the corresponding
+  // TBAATypeDescriptorOp. It must be populated during the type conversion.
+  // Currently unused.
+  llvm::DenseMap<mlir::Type, mlir::SymbolRefAttr> typeDescMap;
+
+  // Each TBAA tag is a tuple of <baseTypeSym, accessTypeSym, offset>.
+  // This map holds TBAATagOp symbol for each unique tuple.
+  llvm::DenseMap<std::tuple<mlir::SymbolRefAttr, mlir::SymbolRefAttr, int64_t>,
+                 mlir::SymbolRefAttr>
+      tagsMap;
+};
+
+} // namespace fir
+
+#endif // FORTRAN_OPTIMIZER_CODEGEN_TBAABUILDER_H

flang/lib/Optimizer/CodeGen/TBAABuilder.cpp

+//===-- TBAABuilder.cpp -- TBAA builder definitions -----------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Coding style: https://mlir.llvm.org/getting_started/DeveloperGuide/
+//
+//===----------------------------------------------------------------------===//
+
+#include "TBAABuilder.h"
+#include "flang/Optimizer/Dialect/FIRType.h"
+#include "llvm/Support/CommandLine.h"
+
+using namespace mlir;
+using namespace mlir::LLVM;
+
+static llvm::cl::opt<bool> disableTBAA(
+    "disable-tbaa",
+    llvm::cl::desc("disable attaching TBAA tags to memory accessing operations "
+                   "to override default Flang behavior"),
+    llvm::cl::init(false));
+
+namespace fir {
+std::string TBAABuilder::getNewTBAANodeName(llvm::StringRef basename) {
+  return (llvm::Twine(basename) + llvm::Twine('_') +
+          llvm::Twine(tbaaNodeCounter++))
+      .str();
+}
+
+TBAABuilder::TBAABuilder(mlir::ModuleOp module, bool applyTBAA)
+    : enableTBAA(applyTBAA && !disableTBAA) {
+  if (!enableTBAA)
+    return;
+
+  // In usual Flang compilation flow, FIRToLLVMPass is run once,
+  // and the MetadataOp holding TBAA operations is created at the beginning
+  // of the pass. With tools like tco it is possible to invoke
+  // FIRToLLVMPass on already converted MLIR, so the MetadataOp
+  // already exists and creating a new one with the same name would
+  // be incorrect. If the TBAA MetadataOp is already present,
+  // we just disable all TBAABuilder actions (e.g. attachTBAATag()
+  // is a no-op).
+  if (llvm::any_of(
+          module.getBodyRegion().getOps<LLVM::MetadataOp>(),
+          [&](auto metaOp) { return metaOp.getSymName() == tbaaMetaOpName; })) {
+    enableTBAA = false;
+    return;
+  }
+
+  // Create TBAA MetadataOp with the root and basic type descriptors.
+  Location loc = module.getLoc();
+  MLIRContext *context = module.getContext();
+  OpBuilder builder(module.getBody(), module.getBody()->end());
+  tbaaMetaOp = builder.create<MetadataOp>(loc, tbaaMetaOpName);
+  builder.setInsertionPointToStart(&tbaaMetaOp.getBody().front());
+
+  // Root node.
+  auto rootOp = builder.create<TBAARootMetadataOp>(
+      loc, getNewTBAANodeName(kRootSymBasename), flangTBAARootId);
+  flangTBAARoot = FlatSymbolRefAttr::get(rootOp);
+
+  // Any access node.
+  auto anyAccessOp = builder.create<TBAATypeDescriptorOp>(
+      loc, getNewTBAANodeName(kTypeDescSymBasename),
+      StringAttr::get(context, anyAccessTypeDescId),
+      ArrayAttr::get(context, flangTBAARoot), ArrayRef<int64_t>{0});
+  anyAccessTypeDesc = FlatSymbolRefAttr::get(anyAccessOp);
+
+  // Any data access node.
+  auto anyDataAccessOp = builder.create<TBAATypeDescriptorOp>(
+      loc, getNewTBAANodeName(kTypeDescSymBasename),
+      StringAttr::get(context, anyDataAccessTypeDescId),
+      ArrayAttr::get(context, anyAccessTypeDesc), ArrayRef<int64_t>{0});
+  anyDataAccessTypeDesc = FlatSymbolRefAttr::get(anyDataAccessOp);
+
+  // Box member access node.
+  auto boxMemberOp = builder.create<TBAATypeDescriptorOp>(
+      loc, getNewTBAANodeName(kTypeDescSymBasename),
+      StringAttr::get(context, boxMemberTypeDescId),
+      ArrayAttr::get(context, anyAccessTypeDesc), ArrayRef<int64_t>{0});
+  boxMemberTypeDesc = FlatSymbolRefAttr::get(boxMemberOp);
+}
+
+SymbolRefAttr TBAABuilder::getAccessTag(SymbolRefAttr baseTypeDesc,
+                                        SymbolRefAttr accessTypeDesc,
+                                        int64_t offset) {
+  SymbolRefAttr &tag = tagsMap[{baseTypeDesc, accessTypeDesc, offset}];
+  if (tag)
+    return tag;
+
+  // Initialize new tag.
+  Location loc = tbaaMetaOp.getLoc();
+  OpBuilder builder(&tbaaMetaOp.getBody().back(),
+                    tbaaMetaOp.getBody().back().end());
+  auto tagOp = builder.create<TBAATagOp>(
+      loc, getNewTBAANodeName(kTagSymBasename), baseTypeDesc.getLeafReference(),
+      accessTypeDesc.getLeafReference(), offset);
+  // TBAATagOp symbols must be referenced by their fully qualified
+  // names, so create a path to TBAATagOp symbol.
+  StringAttr metaOpName = SymbolTable::getSymbolName(tbaaMetaOp);
+  tag = SymbolRefAttr::get(builder.getContext(), metaOpName,
+                           FlatSymbolRefAttr::get(tagOp));
+  return tag;
+}
+
+SymbolRefAttr TBAABuilder::getAnyBoxAccessTag() {
+  return getAccessTag(boxMemberTypeDesc, boxMemberTypeDesc, /*offset=*/0);
+}
+
+SymbolRefAttr TBAABuilder::getBoxAccessTag(Type baseFIRType, Type accessFIRType,
+                                           GEPOp gep) {
+  return getAnyBoxAccessTag();
+}
+
+SymbolRefAttr TBAABuilder::getAnyDataAccessTag() {
+  return getAccessTag(anyDataAccessTypeDesc, anyDataAccessTypeDesc,
+                      /*offset=*/0);
+}
+
+SymbolRefAttr TBAABuilder::getDataAccessTag(Type baseFIRType,
+                                            Type accessFIRType, GEPOp gep) {
+  return getAnyDataAccessTag();
+}
+
+void TBAABuilder::attachTBAATag(Operation *op, Type baseFIRType,
+                                Type accessFIRType, GEPOp gep) {
+  if (!enableTBAA)
+    return;
+
+  SymbolRefAttr tbaaTagSym;
+  if (baseFIRType.isa<fir::BaseBoxType>())
+    tbaaTagSym = getBoxAccessTag(baseFIRType, accessFIRType, gep);
+  else
+    tbaaTagSym = getDataAccessTag(baseFIRType, accessFIRType, gep);
+
+  if (tbaaTagSym)
+    op->setAttr(LLVMDialect::getTBAAAttrName(),
+                ArrayAttr::get(op->getContext(), tbaaTagSym));
+}
+
+} // namespace fir

flang/lib/Optimizer/CodeGen/TypeConverter.h

 //===-- TypeConverter.h -- type conversion ----------------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // Coding style: https://mlir.llvm.org/getting_started/DeveloperGuide/
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef FORTRAN_OPTIMIZER_CODEGEN_TYPECONVERTER_H
 #define FORTRAN_OPTIMIZER_CODEGEN_TYPECONVERTER_H
 
 #include "DescriptorModel.h"
+#include "TBAABuilder.h"
 #include "Target.h"
 #include "flang/Optimizer/Builder/Todo.h" // remove when TODO's are done
 #include "flang/Optimizer/Dialect/FIRType.h"
 #include "flang/Optimizer/Support/FIRContext.h"
 #include "flang/Optimizer/Support/KindMapping.h"
 #include "mlir/Conversion/LLVMCommon/TypeConverter.h"
 #include "llvm/Support/Debug.h"
 

 static constexpr unsigned kDimStridePos = 2;
 
 namespace fir {
 
 /// FIR type converter
 /// This converts FIR types to LLVM types (for now)
 class LLVMTypeConverter : public mlir::LLVMTypeConverter {
 public:
-  LLVMTypeConverter(mlir::ModuleOp module)
+  LLVMTypeConverter(mlir::ModuleOp module, bool applyTBAA)
       : mlir::LLVMTypeConverter(module.getContext()),
         kindMapping(getKindMapping(module)),
         specifics(CodeGenSpecifics::get(module.getContext(),
                                         getTargetTriple(module),
-                                        getKindMapping(module))) {
+                                        getKindMapping(module))),
+        tbaaBuilder(module, applyTBAA) {
     LLVM_DEBUG(llvm::dbgs() << "FIR type converter\n");
 
     // Each conversion should return a value of type mlir::Type.
     addConversion([&](BoxType box) { return convertBoxType(box); });
     addConversion([&](BoxCharType boxchar) {
       LLVM_DEBUG(llvm::dbgs() << "type convert: " << boxchar << '\n');
       return convertType(specifics->boxcharMemoryType(boxchar.getEleTy()));
     });
if (requiresExtendedDesc(ele) || fir::isUnlimitedPolymorphicType(box)) {
           // polymorphic allocatables, it seems all length parameters cannot
           // always possibly be placed in the addendum.
           TODO_NOLOC("extended descriptor derived with length parameters");
           unsigned numLenParams = recTy.getNumLenParams();
           dataDescFields.push_back(
               mlir::LLVM::LLVMArrayType::get(rowTy, numLenParams));
         }
     }
+    // TODO: send the box type and the converted LLVM structure layout
+    // to tbaaBuilder for proper creation of TBAATypeDescriptorOp.
     return mlir::LLVM::LLVMPointerType::get(
         mlir::LLVM::LLVMStructType::getLiteral(&getContext(), dataDescFields,
                                                /*isPacked=*/false));
   }
 
   /// Convert fir.box type to the corresponding llvm struct type instead of a
   /// pointer to this struct type.
   mlir::Type convertBoxTypeAsStruct(BaseBoxType box) {
public:
   // the f18 object v. class distinction (F2003).
   mlir::Type convertTypeDescType(mlir::MLIRContext *ctx) {
     return mlir::LLVM::LLVMPointerType::get(
         mlir::IntegerType::get(&getContext(), 8));
   }
 
   KindMapping &getKindMap() { return kindMapping; }
 
+  // Relay TBAA tag attachment to TBAABuilder.
+  void attachTBAATag(mlir::Operation *op, mlir::Type baseFIRType,
+                     mlir::Type accessFIRType, mlir::LLVM::GEPOp gep) {
+    tbaaBuilder.attachTBAATag(op, baseFIRType, accessFIRType, gep);
+  }
+
 private:
   KindMapping kindMapping;
   std::unique_ptr<CodeGenSpecifics> specifics;
+  TBAABuilder tbaaBuilder;
 };
 
 } // namespace fir
 
 #endif // FORTRAN_OPTIMIZER_CODEGEN_TYPECONVERTER_H

flang/test/Fir/tbaa.fir

+// RUN: fir-opt %s --split-input-file --fir-to-llvm-ir="target=x86_64-unknown-linux-gnu apply-tbaa=true" | FileCheck %s
+// RUN: fir-opt %s --split-input-file --fir-to-llvm-ir="target=aarch64-unknown-linux-gnu apply-tbaa=true" | FileCheck %s
+
+module {
+  func.func @tbaa(%arg0: !fir.class<!fir.array<?xnone>> {fir.bindc_name = "a"}) {
+    %c9_i8 = arith.constant 9 : i8
+    %c0_i64 = arith.constant 0 : i64
+    %c10_i32 = arith.constant 10 : i32
+    %0 = fir.coordinate_of %arg0, %c0_i64 : (!fir.class<!fir.array<?xnone>>, i64) -> !fir.ref<none>
+    %1 = fir.embox %0 source_box %arg0 : (!fir.ref<none>, !fir.class<!fir.array<?xnone>>) -> !fir.class<none>
+    %2 = fir.box_typecode %1 : (!fir.class<none>) -> i8
+    %3 = arith.cmpi eq, %2, %c9_i8 : i8
+    cf.cond_br %3, ^bb1, ^bb2
+  ^bb1:  // pred: ^bb0
+    %4 = fir.box_addr %1 : (!fir.class<none>) -> !fir.ref<i32>
+    fir.store %c10_i32 to %4 : !fir.ref<i32>
+    cf.br ^bb2
+  ^bb2:  // 2 preds: ^bb0, ^bb1
+    return
+  }
+}
+
+// CHECK-LABEL:   llvm.func @tbaa(
+// CHECK-SAME:                    %[[VAL_0:.*]]: !llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>> {fir.bindc_name = "a"}) {
+// CHECK:           %[[VAL_1:.*]] = llvm.mlir.constant(1 : i32) : i32
+// CHECK:           %[[VAL_2:.*]] = llvm.alloca %[[VAL_1]] x !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, ptr<i8>, array<1 x i64>)> {alignment = 8 : i64} : (i32) -> !llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, ptr<i8>, array<1 x i64>)>>
+// CHECK:           %[[VAL_3:.*]] = llvm.mlir.constant(9 : i8) : i8
+// CHECK:           %[[VAL_4:.*]] = llvm.mlir.constant(0 : i64) : i64
+// CHECK:           %[[VAL_5:.*]] = llvm.mlir.constant(10 : i32) : i32
+// CHECK:           %[[VAL_6:.*]] = llvm.getelementptr %[[VAL_0]][0, 0] : (!llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>) -> !llvm.ptr<ptr<struct<()>>>
+// CHECK:           %[[VAL_7:.*]] = llvm.load %[[VAL_6]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT:tag_[0-9]*]]]} : !llvm.ptr<ptr<struct<()>>>
+// CHECK:           %[[VAL_8:.*]] = llvm.mlir.constant(0 : i64) : i64
+// CHECK:           %[[VAL_9:.*]] = llvm.getelementptr %[[VAL_0]][0, 7, 0, 2] : (!llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>) -> !llvm.ptr<i64>
+// CHECK:           %[[VAL_10:.*]] = llvm.load %[[VAL_9]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT]]]} : !llvm.ptr<i64>
+// CHECK:           %[[VAL_11:.*]] = llvm.mul %[[VAL_4]], %[[VAL_10]]  : i64
+// CHECK:           %[[VAL_12:.*]] = llvm.add %[[VAL_11]], %[[VAL_8]]  : i64
+// CHECK:           %[[VAL_13:.*]] = llvm.bitcast %[[VAL_7]] : !llvm.ptr<struct<()>> to !llvm.ptr<i8>
+// CHECK:           %[[VAL_14:.*]] = llvm.getelementptr %[[VAL_13]]{{\[}}%[[VAL_12]]] : (!llvm.ptr<i8>, i64) -> !llvm.ptr<i8>
+// CHECK:           %[[VAL_15:.*]] = llvm.bitcast %[[VAL_14]] : !llvm.ptr<i8> to !llvm.ptr<struct<()>>
+// CHECK:           %[[VAL_16:.*]] = llvm.mlir.constant(0 : i64) : i64
+// CHECK:           %[[VAL_17:.*]] = llvm.mlir.constant(-1 : i32) : i32
+// CHECK:           %[[VAL_18:.*]] = llvm.getelementptr %[[VAL_0]][0, 8] : (!llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>) -> !llvm.ptr<ptr<i8>>
+// CHECK:           %[[VAL_19:.*]] = llvm.load %[[VAL_18]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT]]]} : !llvm.ptr<ptr<i8>>
+// CHECK:           %[[VAL_20:.*]] = llvm.getelementptr %[[VAL_0]][0, 1] : (!llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>) -> !llvm.ptr<i64>
+// CHECK:           %[[VAL_21:.*]] = llvm.load %[[VAL_20]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT]]]} : !llvm.ptr<i64>
+// CHECK:           %[[VAL_22:.*]] = llvm.getelementptr %[[VAL_0]][0, 4] : (!llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>) -> !llvm.ptr<i32>
+// CHECK:           %[[VAL_23:.*]] = llvm.load %[[VAL_22]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT]]]} : !llvm.ptr<i32>
+// CHECK:           %[[VAL_24:.*]] = llvm.mlir.undef : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_25:.*]] = llvm.insertvalue %[[VAL_21]], %[[VAL_24]][1] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_26:.*]] = llvm.mlir.constant(20180515 : i32) : i32
+// CHECK:           %[[VAL_27:.*]] = llvm.insertvalue %[[VAL_26]], %[[VAL_25]][2] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_28:.*]] = llvm.mlir.constant(0 : i32) : i32
+// CHECK:           %[[VAL_29:.*]] = llvm.trunc %[[VAL_28]] : i32 to i8
+// CHECK:           %[[VAL_30:.*]] = llvm.insertvalue %[[VAL_29]], %[[VAL_27]][3] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_31:.*]] = llvm.trunc %[[VAL_23]] : i32 to i8
+// CHECK:           %[[VAL_32:.*]] = llvm.insertvalue %[[VAL_31]], %[[VAL_30]][4] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_33:.*]] = llvm.mlir.constant(0 : i32) : i32
+// CHECK:           %[[VAL_34:.*]] = llvm.trunc %[[VAL_33]] : i32 to i8
+// CHECK:           %[[VAL_35:.*]] = llvm.insertvalue %[[VAL_34]], %[[VAL_32]][5] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_36:.*]] = llvm.mlir.constant(1 : i32) : i32
+// CHECK:           %[[VAL_37:.*]] = llvm.trunc %[[VAL_36]] : i32 to i8
+// CHECK:           %[[VAL_38:.*]] = llvm.insertvalue %[[VAL_37]], %[[VAL_35]][6] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_39:.*]] = llvm.bitcast %[[VAL_19]] : !llvm.ptr<i8> to !llvm.ptr<i8>
+// CHECK:           %[[VAL_40:.*]] = llvm.insertvalue %[[VAL_39]], %[[VAL_38]][7] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_41:.*]] = llvm.bitcast %[[VAL_15]] : !llvm.ptr<struct<()>> to !llvm.ptr<struct<()>>
+// CHECK:           %[[VAL_42:.*]] = llvm.insertvalue %[[VAL_41]], %[[VAL_40]][0] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, ptr<i8>, array<1 x i64>)>
+// CHECK:           llvm.store %[[VAL_42]], %[[VAL_2]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT]]]} : !llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, ptr<i8>, array<1 x i64>)>>
+// CHECK:           %[[VAL_43:.*]] = llvm.getelementptr %[[VAL_2]][0, 4] : (!llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, ptr<i8>, array<1 x i64>)>>) -> !llvm.ptr<i8>
+// CHECK:           %[[VAL_44:.*]] = llvm.load %[[VAL_43]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT]]]} : !llvm.ptr<i8>
+// CHECK:           %[[VAL_45:.*]] = llvm.icmp "eq" %[[VAL_44]], %[[VAL_3]] : i8
+// CHECK:           llvm.cond_br %[[VAL_45]], ^bb1, ^bb2
+// CHECK:         ^bb1:
+// CHECK:           %[[VAL_46:.*]] = llvm.getelementptr %[[VAL_2]][0, 0] : (!llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, ptr<i8>, array<1 x i64>)>>) -> !llvm.ptr<ptr<i32>>
+// CHECK:           %[[VAL_47:.*]] = llvm.load %[[VAL_46]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT]]]} : !llvm.ptr<ptr<i32>>
+// CHECK:           llvm.store %[[VAL_5]], %[[VAL_47]] {llvm.tbaa = [@__flang_tbaa::@[[DATAT:tag_[0-9]*]]]} : !llvm.ptr<i32>
+// CHECK:           llvm.br ^bb2
+// CHECK:         ^bb2:
+// CHECK:           llvm.return
+// CHECK:         }
+
+// CHECK-LABEL:   llvm.metadata @__flang_tbaa {
+// CHECK:           llvm.tbaa_root @[[ROOT:root_[0-9]*]] {id = "Flang Type TBAA Root"}
+// CHECK:           llvm.tbaa_type_desc @[[ANYACC:type_desc_[0-9]*]] {id = "any access", members = {<@[[ROOT]], 0>}}
+// CHECK:           llvm.tbaa_type_desc @[[ANYDACC:type_desc_[0-9]*]] {id = "any data access", members = {<@[[ANYACC]], 0>}}
+// CHECK:           llvm.tbaa_type_desc @[[BOXMEM:type_desc_[0-9]*]] {id = "descriptor member", members = {<@[[ANYACC]], 0>}}
+// CHECK:           llvm.tbaa_tag @[[BOXT]] {access_type = @[[BOXMEM]], base_type = @[[BOXMEM]], offset = 0 : i64}
+// CHECK:           llvm.tbaa_tag @[[DATAT]] {access_type = @[[ANYDACC]], base_type = @[[ANYDACC]], offset = 0 : i64}
+// CHECK:         }
+
+// -----
+
+module {
+  func.func @tbaa() {
+    %c0 = arith.constant 0 : index
+    %c8_i32 = arith.constant 8 : i32
+    %c-1_i32 = arith.constant -1 : i32
+    %0 = fir.address_of(@_QFEx) : !fir.ref<!fir.class<!fir.ptr<!fir.array<?xnone>>>>
+    %1 = fir.address_of(@_QQcl.2E2F64756D6D792E66393000) : !fir.ref<!fir.char<1,12>>
+    %2 = fir.convert %1 : (!fir.ref<!fir.char<1,12>>) -> !fir.ref<i8>
+    %3 = fir.call @_FortranAioBeginExternalListOutput(%c-1_i32, %2, %c8_i32) fastmath<contract> : (i32, !fir.ref<i8>, i32) -> !fir.ref<i8>
+    %4 = fir.load %0 : !fir.ref<!fir.class<!fir.ptr<!fir.array<?xnone>>>>
+    %5:3 = fir.box_dims %4, %c0 : (!fir.class<!fir.ptr<!fir.array<?xnone>>>, index) -> (index, index, index)
+    %6 = fircg.ext_rebox %4 origin %5#0 : (!fir.class<!fir.ptr<!fir.array<?xnone>>>, index) -> !fir.class<!fir.array<?xnone>>
+    %7 = fir.convert %6 : (!fir.class<!fir.array<?xnone>>) -> !fir.box<none>
+    %8 = fir.call @_FortranAioOutputDescriptor(%3, %7) fastmath<contract> : (!fir.ref<i8>, !fir.box<none>) -> i1
+    %9 = fir.call @_FortranAioEndIoStatement(%3) fastmath<contract> : (!fir.ref<i8>) -> i32
+    return
+  }
+  func.func private @_FortranAioBeginExternalListOutput(i32, !fir.ref<i8>, i32) -> !fir.ref<i8> attributes {fir.io, fir.runtime}
+  func.func private @_FortranAioOutputDescriptor(!fir.ref<i8>, !fir.box<none>) -> i1 attributes {fir.io, fir.runtime}
+  func.func private @_FortranAioEndIoStatement(!fir.ref<i8>) -> i32 attributes {fir.io, fir.runtime}
+  fir.global linkonce @_QQcl.2E2F64756D6D792E66393000 constant : !fir.char<1,12> {
+    %0 = fir.string_lit "./dummy.f90\00"(12) : !fir.char<1,12>
+    fir.has_value %0 : !fir.char<1,12>
+  }
+  fir.global internal @_QFEx : !fir.class<!fir.ptr<!fir.array<?xnone>>> {
+    %c0 = arith.constant 0 : index
+    %0 = fir.zero_bits !fir.ptr<!fir.array<?xnone>>
+    %1 = fircg.ext_embox %0(%c0) : (!fir.ptr<!fir.array<?xnone>>, index) -> !fir.class<!fir.ptr<!fir.array<?xnone>>>
+    fir.has_value %1 : !fir.class<!fir.ptr<!fir.array<?xnone>>>
+  }
+}
+
+// CHECK-LABEL:   llvm.func @tbaa() {
+// CHECK:           %[[VAL_0:.*]] = llvm.mlir.constant(1 : i32) : i32
+// CHECK:           %[[VAL_1:.*]] = llvm.alloca %[[VAL_0]] x !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)> {alignment = 8 : i64} : (i32) -> !llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>
+// CHECK:           %[[VAL_2:.*]] = llvm.mlir.constant(1 : i32) : i32
+// CHECK:           %[[VAL_3:.*]] = llvm.alloca %[[VAL_2]] x !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)> {alignment = 8 : i64} : (i32) -> !llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>
+// CHECK:           %[[VAL_4:.*]] = llvm.mlir.constant(0 : index) : i64
+// CHECK:           %[[VAL_5:.*]] = llvm.mlir.constant(8 : i32) : i32
+// CHECK:           %[[VAL_6:.*]] = llvm.mlir.constant(-1 : i32) : i32
+// CHECK:           %[[VAL_7:.*]] = llvm.mlir.addressof @_QFEx : !llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>
+// CHECK:           %[[VAL_8:.*]] = llvm.mlir.addressof @_QQcl.2E2F64756D6D792E66393000 : !llvm.ptr<array<12 x i8>>
+// CHECK:           %[[VAL_9:.*]] = llvm.bitcast %[[VAL_8]] : !llvm.ptr<array<12 x i8>> to !llvm.ptr<i8>
+// CHECK:           %[[VAL_10:.*]] = llvm.call @_FortranAioBeginExternalListOutput(%[[VAL_6]], %[[VAL_9]], %[[VAL_5]]) {fastmathFlags = #llvm.fastmath<contract>} : (i32, !llvm.ptr<i8>, i32) -> !llvm.ptr<i8>
+// CHECK:           %[[VAL_11:.*]] = llvm.load %[[VAL_7]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT:tag_[0-9]*]]]} : !llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>
+// CHECK:           llvm.store %[[VAL_11]], %[[VAL_3]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT]]]} : !llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>
+// CHECK:           %[[VAL_12:.*]] = llvm.getelementptr %[[VAL_3]][0, 7, %[[VAL_4]], 0] : (!llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>, i64) -> !llvm.ptr<i64>
+// CHECK:           %[[VAL_13:.*]] = llvm.load %[[VAL_12]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT]]]} : !llvm.ptr<i64>
+// CHECK:           %[[VAL_14:.*]] = llvm.getelementptr %[[VAL_3]][0, 7, %[[VAL_4]], 1] : (!llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>, i64) -> !llvm.ptr<i64>
+// CHECK:           %[[VAL_15:.*]] = llvm.load %[[VAL_14]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT]]]} : !llvm.ptr<i64>
+// CHECK:           %[[VAL_16:.*]] = llvm.getelementptr %[[VAL_3]][0, 7, %[[VAL_4]], 2] : (!llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>, i64) -> !llvm.ptr<i64>
+// CHECK:           %[[VAL_17:.*]] = llvm.load %[[VAL_16]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT]]]} : !llvm.ptr<i64>
+// CHECK:           %[[VAL_18:.*]] = llvm.getelementptr %[[VAL_3]][0, 8] : (!llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>) -> !llvm.ptr<ptr<i8>>
+// CHECK:           %[[VAL_19:.*]] = llvm.load %[[VAL_18]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT]]]} : !llvm.ptr<ptr<i8>>
+// CHECK:           %[[VAL_20:.*]] = llvm.mlir.constant(0 : i64) : i64
+// CHECK:           %[[VAL_21:.*]] = llvm.mlir.constant(-1 : i32) : i32
+// CHECK:           %[[VAL_22:.*]] = llvm.getelementptr %[[VAL_3]][0, 1] : (!llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>) -> !llvm.ptr<i64>
+// CHECK:           %[[VAL_23:.*]] = llvm.load %[[VAL_22]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT]]]} : !llvm.ptr<i64>
+// CHECK:           %[[VAL_24:.*]] = llvm.getelementptr %[[VAL_3]][0, 4] : (!llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>) -> !llvm.ptr<i32>
+// CHECK:           %[[VAL_25:.*]] = llvm.load %[[VAL_24]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT]]]} : !llvm.ptr<i32>
+// CHECK:           %[[VAL_26:.*]] = llvm.getelementptr %[[VAL_3]][0, 8] : (!llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>) -> !llvm.ptr<ptr<i8>>
+// CHECK:           %[[VAL_27:.*]] = llvm.load %[[VAL_26]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT]]]} : !llvm.ptr<ptr<i8>>
+// CHECK:           %[[VAL_28:.*]] = llvm.mlir.undef : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_29:.*]] = llvm.insertvalue %[[VAL_23]], %[[VAL_28]][1] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_30:.*]] = llvm.mlir.constant(20180515 : i32) : i32
+// CHECK:           %[[VAL_31:.*]] = llvm.insertvalue %[[VAL_30]], %[[VAL_29]][2] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_32:.*]] = llvm.mlir.constant(1 : i32) : i32
+// CHECK:           %[[VAL_33:.*]] = llvm.trunc %[[VAL_32]] : i32 to i8
+// CHECK:           %[[VAL_34:.*]] = llvm.insertvalue %[[VAL_33]], %[[VAL_31]][3] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_35:.*]] = llvm.trunc %[[VAL_25]] : i32 to i8
+// CHECK:           %[[VAL_36:.*]] = llvm.insertvalue %[[VAL_35]], %[[VAL_34]][4] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_37:.*]] = llvm.mlir.constant(0 : i32) : i32
+// CHECK:           %[[VAL_38:.*]] = llvm.trunc %[[VAL_37]] : i32 to i8
+// CHECK:           %[[VAL_39:.*]] = llvm.insertvalue %[[VAL_38]], %[[VAL_36]][5] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_40:.*]] = llvm.mlir.constant(1 : i32) : i32
+// CHECK:           %[[VAL_41:.*]] = llvm.trunc %[[VAL_40]] : i32 to i8
+// CHECK:           %[[VAL_42:.*]] = llvm.insertvalue %[[VAL_41]], %[[VAL_39]][6] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_43:.*]] = llvm.bitcast %[[VAL_27]] : !llvm.ptr<i8> to !llvm.ptr<i8>
+// CHECK:           %[[VAL_44:.*]] = llvm.insertvalue %[[VAL_43]], %[[VAL_42]][8] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_45:.*]] = llvm.getelementptr %[[VAL_3]][0, 7, 0, 0] : (!llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>) -> !llvm.ptr<i64>
+// CHECK:           %[[VAL_46:.*]] = llvm.load %[[VAL_45]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT]]]} : !llvm.ptr<i64>
+// CHECK:           %[[VAL_47:.*]] = llvm.getelementptr %[[VAL_3]][0, 7, 0, 1] : (!llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>) -> !llvm.ptr<i64>
+// CHECK:           %[[VAL_48:.*]] = llvm.load %[[VAL_47]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT]]]} : !llvm.ptr<i64>
+// CHECK:           %[[VAL_49:.*]] = llvm.getelementptr %[[VAL_3]][0, 7, 0, 2] : (!llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>) -> !llvm.ptr<i64>
+// CHECK:           %[[VAL_50:.*]] = llvm.load %[[VAL_49]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT]]]} : !llvm.ptr<i64>
+// CHECK:           %[[VAL_51:.*]] = llvm.getelementptr %[[VAL_3]][0, 0] : (!llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>) -> !llvm.ptr<ptr<struct<()>>>
+// CHECK:           %[[VAL_52:.*]] = llvm.load %[[VAL_51]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT]]]} : !llvm.ptr<ptr<struct<()>>>
+// CHECK:           %[[VAL_53:.*]] = llvm.mlir.constant(0 : i64) : i64
+// CHECK:           %[[VAL_54:.*]] = llvm.mlir.constant(1 : i64) : i64
+// CHECK:           %[[VAL_55:.*]] = llvm.icmp "eq" %[[VAL_48]], %[[VAL_53]] : i64
+// CHECK:           %[[VAL_56:.*]] = llvm.select %[[VAL_55]], %[[VAL_54]], %[[VAL_13]] : i1, i64
+// CHECK:           %[[VAL_57:.*]] = llvm.insertvalue %[[VAL_56]], %[[VAL_44]][7, 0, 0] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_58:.*]] = llvm.insertvalue %[[VAL_48]], %[[VAL_57]][7, 0, 1] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_59:.*]] = llvm.insertvalue %[[VAL_50]], %[[VAL_58]][7, 0, 2] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_60:.*]] = llvm.bitcast %[[VAL_52]] : !llvm.ptr<struct<()>> to !llvm.ptr<struct<()>>
+// CHECK:           %[[VAL_61:.*]] = llvm.insertvalue %[[VAL_60]], %[[VAL_59]][0] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           llvm.store %[[VAL_61]], %[[VAL_1]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT]]]} : !llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>>
+// CHECK:           %[[VAL_62:.*]] = llvm.bitcast %[[VAL_1]] : !llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>> to !llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, ptr<i8>, array<1 x i64>)>>
+// CHECK:           %[[VAL_63:.*]] = llvm.call @_FortranAioOutputDescriptor(%[[VAL_10]], %[[VAL_62]]) {fastmathFlags = #llvm.fastmath<contract>} : (!llvm.ptr<i8>, !llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, ptr<i8>, array<1 x i64>)>>) -> i1
+// CHECK:           %[[VAL_64:.*]] = llvm.call @_FortranAioEndIoStatement(%[[VAL_10]]) {fastmathFlags = #llvm.fastmath<contract>} : (!llvm.ptr<i8>) -> i32
+// CHECK:           llvm.return
+// CHECK:         }
+// CHECK:         llvm.func @_FortranAioBeginExternalListOutput(i32, !llvm.ptr<i8>, i32) -> !llvm.ptr<i8> attributes {fir.io, fir.runtime, sym_visibility = "private"}
+// CHECK:         llvm.func @_FortranAioOutputDescriptor(!llvm.ptr<i8>, !llvm.ptr<struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, ptr<i8>, array<1 x i64>)>>) -> i1 attributes {fir.io, fir.runtime, sym_visibility = "private"}
+// CHECK:         llvm.func @_FortranAioEndIoStatement(!llvm.ptr<i8>) -> i32 attributes {fir.io, fir.runtime, sym_visibility = "private"}
+
+// CHECK-LABEL:   llvm.mlir.global linkonce constant @_QQcl.2E2F64756D6D792E66393000() {addr_space = 0 : i32} : !llvm.array<12 x i8> {
+// CHECK:           %[[VAL_0:.*]] = llvm.mlir.constant("./dummy.f90\00") : !llvm.array<12 x i8>
+// CHECK:           llvm.return %[[VAL_0]] : !llvm.array<12 x i8>
+// CHECK:         }
+
+// CHECK-LABEL:   llvm.mlir.global internal @_QFEx() {addr_space = 0 : i32} : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)> {
+// CHECK:           %[[VAL_0:.*]] = llvm.mlir.constant(0 : index) : i64
+// CHECK:           %[[VAL_1:.*]] = llvm.mlir.null : !llvm.ptr<struct<()>>
+// CHECK:           %[[VAL_2:.*]] = llvm.mlir.constant(0 : i64) : i64
+// CHECK:           %[[VAL_3:.*]] = llvm.mlir.constant(-1 : i32) : i32
+// CHECK:           %[[VAL_4:.*]] = llvm.mlir.undef : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_5:.*]] = llvm.insertvalue %[[VAL_2]], %[[VAL_4]][1] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_6:.*]] = llvm.mlir.constant(20180515 : i32) : i32
+// CHECK:           %[[VAL_7:.*]] = llvm.insertvalue %[[VAL_6]], %[[VAL_5]][2] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_8:.*]] = llvm.mlir.constant(1 : i32) : i32
+// CHECK:           %[[VAL_9:.*]] = llvm.trunc %[[VAL_8]] : i32 to i8
+// CHECK:           %[[VAL_10:.*]] = llvm.insertvalue %[[VAL_9]], %[[VAL_7]][3] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_11:.*]] = llvm.trunc %[[VAL_3]] : i32 to i8
+// CHECK:           %[[VAL_12:.*]] = llvm.insertvalue %[[VAL_11]], %[[VAL_10]][4] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_13:.*]] = llvm.mlir.constant(1 : i32) : i32
+// CHECK:           %[[VAL_14:.*]] = llvm.trunc %[[VAL_13]] : i32 to i8
+// CHECK:           %[[VAL_15:.*]] = llvm.insertvalue %[[VAL_14]], %[[VAL_12]][5] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_16:.*]] = llvm.mlir.constant(1 : i32) : i32
+// CHECK:           %[[VAL_17:.*]] = llvm.trunc %[[VAL_16]] : i32 to i8
+// CHECK:           %[[VAL_18:.*]] = llvm.insertvalue %[[VAL_17]], %[[VAL_15]][6] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_19:.*]] = llvm.mlir.null : !llvm.ptr<i8>
+// CHECK:           %[[VAL_20:.*]] = llvm.bitcast %[[VAL_19]] : !llvm.ptr<i8> to !llvm.ptr<i8>
+// CHECK:           %[[VAL_21:.*]] = llvm.insertvalue %[[VAL_20]], %[[VAL_18]][8] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_22:.*]] = llvm.mlir.constant(0 : i64) : i64
+// CHECK:           %[[VAL_23:.*]] = llvm.mlir.constant(1 : i64) : i64
+// CHECK:           %[[VAL_24:.*]] = llvm.insertvalue %[[VAL_23]], %[[VAL_21]][7, 0, 0] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_25:.*]] = llvm.insertvalue %[[VAL_0]], %[[VAL_24]][7, 0, 1] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_26:.*]] = llvm.insertvalue %[[VAL_2]], %[[VAL_25]][7, 0, 2] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           %[[VAL_27:.*]] = llvm.mul %[[VAL_2]], %[[VAL_0]]  : i64
+// CHECK:           %[[VAL_28:.*]] = llvm.mul %[[VAL_23]], %[[VAL_0]]  : i64
+// CHECK:           %[[VAL_29:.*]] = llvm.bitcast %[[VAL_1]] : !llvm.ptr<struct<()>> to !llvm.ptr<struct<()>>
+// CHECK:           %[[VAL_30:.*]] = llvm.insertvalue %[[VAL_29]], %[[VAL_26]][0] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:           llvm.return %[[VAL_30]] : !llvm.struct<(ptr<struct<()>>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>, ptr<i8>, array<1 x i64>)>
+// CHECK:         }
+
+// CHECK-LABEL:   llvm.metadata @__flang_tbaa {
+// CHECK:           llvm.tbaa_root @[[ROOT:root_[0-9]*]] {id = "Flang Type TBAA Root"}
+// CHECK:           llvm.tbaa_type_desc @[[ANYACC:type_desc_[0-9]*]] {id = "any access", members = {<@[[ROOT]], 0>}}
+// CHECK:           llvm.tbaa_type_desc @[[ANYDACC:type_desc_[0-9]*]] {id = "any data access", members = {<@[[ANYACC]], 0>}}
+// CHECK:           llvm.tbaa_type_desc @[[BOXMEM:type_desc_[0-9]*]] {id = "descriptor member", members = {<@[[ANYACC]], 0>}}
+// CHECK:           llvm.tbaa_tag @[[BOXT]] {access_type = @[[BOXMEM]], base_type = @[[BOXMEM]], offset = 0 : i64}
+// CHECK:         }
+
+// -----
+
+func.func @tbaa(%arg0: !fir.box<!fir.array<*:f64>>) -> i32 {
+  %0 = fir.box_rank %arg0 : (!fir.box<!fir.array<*:f64>>) -> i32
+  return %0 : i32
+}
+
+// CHECK-LABEL:   llvm.func @tbaa(
+// CHECK-SAME:                    %[[VAL_0:.*]]: !llvm.ptr<struct<(ptr<f64>, i64, i32, i8, i8, i8, i8)>>) -> i32 {
+// CHECK:           %[[VAL_1:.*]] = llvm.getelementptr %[[VAL_0]][0, 3] : (!llvm.ptr<struct<(ptr<f64>, i64, i32, i8, i8, i8, i8)>>) -> !llvm.ptr<i32>
+// CHECK:           %[[VAL_2:.*]] = llvm.load %[[VAL_1]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT:tag_[0-9]*]]]} : !llvm.ptr<i32>
+// CHECK:           llvm.return %[[VAL_2]] : i32
+// CHECK:         }
+
+// CHECK-LABEL:   llvm.metadata @__flang_tbaa {
+// CHECK:           llvm.tbaa_root @[[ROOT:root_[0-9]*]] {id = "Flang Type TBAA Root"}
+// CHECK:           llvm.tbaa_type_desc @[[ANYACC:type_desc_[0-9]*]] {id = "any access", members = {<@[[ROOT]], 0>}}
+// CHECK:           llvm.tbaa_type_desc @[[ANYDACC:type_desc_[0-9]*]] {id = "any data access", members = {<@[[ANYACC]], 0>}}
+// CHECK:           llvm.tbaa_type_desc @[[BOXMEM:type_desc_[0-9]*]] {id = "descriptor member", members = {<@[[ANYACC]], 0>}}
+// CHECK:           llvm.tbaa_tag @[[BOXT]] {access_type = @[[BOXMEM]], base_type = @[[BOXMEM]], offset = 0 : i64}
+// CHECK:         }
+
+// -----
+
+func.func @tbaa(%arg0: !fir.box<!fir.array<*:f64>>) -> i1 {
+  %0 = fir.box_isarray %arg0 : (!fir.box<!fir.array<*:f64>>) -> i1
+  return %0 : i1
+}
+
+// CHECK-LABEL:   llvm.func @tbaa(
+// CHECK-SAME:                    %[[VAL_0:.*]]: !llvm.ptr<struct<(ptr<f64>, i64, i32, i8, i8, i8, i8)>>) -> i1 {
+// CHECK:           %[[VAL_1:.*]] = llvm.getelementptr %[[VAL_0]][0, 3] : (!llvm.ptr<struct<(ptr<f64>, i64, i32, i8, i8, i8, i8)>>) -> !llvm.ptr<i32>
+// CHECK:           %[[VAL_2:.*]] = llvm.load %[[VAL_1]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT:tag_[0-9]*]]]} : !llvm.ptr<i32>
+// CHECK:           %[[VAL_3:.*]] = llvm.mlir.constant(0 : i32) : i32
+// CHECK:           %[[VAL_4:.*]] = llvm.icmp "ne" %[[VAL_2]], %[[VAL_3]] : i32
+// CHECK:           llvm.return %[[VAL_4]] : i1
+// CHECK:         }
+
+// CHECK-LABEL:   llvm.metadata @__flang_tbaa {
+// CHECK:           llvm.tbaa_root @[[ROOT:root_[0-9]*]] {id = "Flang Type TBAA Root"}
+// CHECK:           llvm.tbaa_type_desc @[[ANYACC:type_desc_[0-9]*]] {id = "any access", members = {<@[[ROOT]], 0>}}
+// CHECK:           llvm.tbaa_type_desc @[[ANYDACC:type_desc_[0-9]*]] {id = "any data access", members = {<@[[ANYACC]], 0>}}
+// CHECK:           llvm.tbaa_type_desc @[[BOXMEM:type_desc_[0-9]*]] {id = "descriptor member", members = {<@[[ANYACC]], 0>}}
+// CHECK:           llvm.tbaa_tag @[[BOXT]] {access_type = @[[BOXMEM]], base_type = @[[BOXMEM]], offset = 0 : i64}
+// CHECK:         }
+
+// -----
+
+func.func @tbaa(%arg0: !fir.box<f32>) -> i32 {
+  %0 = fir.box_elesize %arg0 : (!fir.box<f32>) -> i32
+  return %0 : i32
+}
+
+// CHECK-LABEL:   llvm.func @tbaa(
+// CHECK-SAME:                               %[[VAL_0:.*]]: !llvm.ptr<struct<(ptr<f32>, i64, i32, i8, i8, i8, i8)>>) -> i32 {
+// CHECK:           %[[VAL_1:.*]] = llvm.getelementptr %[[VAL_0]][0, 1] : (!llvm.ptr<struct<(ptr<f32>, i64, i32, i8, i8, i8, i8)>>) -> !llvm.ptr<i32>
+// CHECK:           %[[VAL_2:.*]] = llvm.load %[[VAL_1]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT:tag_[0-9]*]]]} : !llvm.ptr<i32>
+// CHECK:           llvm.return %[[VAL_2]] : i32
+// CHECK:         }
+
+// CHECK-LABEL:   llvm.metadata @__flang_tbaa {
+// CHECK:           llvm.tbaa_root @[[ROOT:root_[0-9]*]] {id = "Flang Type TBAA Root"}
+// CHECK:           llvm.tbaa_type_desc @[[ANYACC:type_desc_[0-9]*]] {id = "any access", members = {<@[[ROOT]], 0>}}
+// CHECK:           llvm.tbaa_type_desc @[[ANYDACC:type_desc_[0-9]*]] {id = "any data access", members = {<@[[ANYACC]], 0>}}
+// CHECK:           llvm.tbaa_type_desc @[[BOXMEM:type_desc_[0-9]*]] {id = "descriptor member", members = {<@[[ANYACC]], 0>}}
+// CHECK:           llvm.tbaa_tag @[[BOXT]] {access_type = @[[BOXMEM]], base_type = @[[BOXMEM]], offset = 0 : i64}
+// CHECK:         }
+
+// -----
+
+func.func @tbaa(%arg0: !fir.box<!fir.array<*:f64>>) -> i1 {
+  %0 = fir.box_isalloc %arg0 : (!fir.box<!fir.array<*:f64>>) -> i1
+  return %0 : i1
+}
+
+// CHECK-LABEL:   llvm.func @tbaa(
+// CHECK-SAME:                    %[[VAL_0:.*]]: !llvm.ptr<struct<(ptr<f64>, i64, i32, i8, i8, i8, i8)>>) -> i1 {
+// CHECK:           %[[VAL_1:.*]] = llvm.getelementptr %[[VAL_0]][0, 5] : (!llvm.ptr<struct<(ptr<f64>, i64, i32, i8, i8, i8, i8)>>) -> !llvm.ptr<i32>
+// CHECK:           %[[VAL_2:.*]] = llvm.load %[[VAL_1]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT:tag_[0-9]*]]]} : !llvm.ptr<i32>
+// CHECK:           %[[VAL_3:.*]] = llvm.mlir.constant(2 : i32) : i32
+// CHECK:           %[[VAL_4:.*]] = llvm.and %[[VAL_2]], %[[VAL_3]]  : i32
+// CHECK:           %[[VAL_5:.*]] = llvm.mlir.constant(0 : i32) : i32
+// CHECK:           %[[VAL_6:.*]] = llvm.icmp "ne" %[[VAL_4]], %[[VAL_5]] : i32
+// CHECK:           llvm.return %[[VAL_6]] : i1
+// CHECK:         }
+
+// CHECK-LABEL:   llvm.metadata @__flang_tbaa {
+// CHECK:           llvm.tbaa_root @[[ROOT:root_[0-9]*]] {id = "Flang Type TBAA Root"}
+// CHECK:           llvm.tbaa_type_desc @[[ANYACC:type_desc_[0-9]*]] {id = "any access", members = {<@[[ROOT]], 0>}}
+// CHECK:           llvm.tbaa_type_desc @[[ANYDACC:type_desc_[0-9]*]] {id = "any data access", members = {<@[[ANYACC]], 0>}}
+// CHECK:           llvm.tbaa_type_desc @[[BOXMEM:type_desc_[0-9]*]] {id = "descriptor member", members = {<@[[ANYACC]], 0>}}
+// CHECK:           llvm.tbaa_tag @[[BOXT]] {access_type = @[[BOXMEM]], base_type = @[[BOXMEM]], offset = 0 : i64}
+// CHECK:         }
+
+// -----
+
+func.func @tbaa(%arg0: !fir.box<!fir.array<?xi32>>) {
+  %c0 = arith.constant 0 : i64
+  %1 = fircg.ext_array_coor %arg0(%c0) <%c0> : (!fir.box<!fir.array<?xi32>>, i64, i64) -> !fir.ref<i32>
+  return
+}
+
+// CHECK-LABEL:   llvm.func @tbaa(
+// CHECK-SAME:                    %[[VAL_0:.*]]: !llvm.ptr<struct<(ptr<i32>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>)>>) {
+// CHECK:           %[[VAL_1:.*]] = llvm.mlir.constant(0 : i64) : i64
+// CHECK:           %[[VAL_2:.*]] = llvm.mlir.constant(1 : i64) : i64
+// CHECK:           %[[VAL_3:.*]] = llvm.mlir.constant(0 : i64) : i64
+// CHECK:           %[[VAL_4:.*]] = llvm.sub %[[VAL_1]], %[[VAL_2]]  : i64
+// CHECK:           %[[VAL_5:.*]] = llvm.mul %[[VAL_4]], %[[VAL_2]]  : i64
+// CHECK:           %[[VAL_6:.*]] = llvm.getelementptr %[[VAL_0]][0, 7, 0, 2] : (!llvm.ptr<struct<(ptr<i32>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>)>>) -> !llvm.ptr<i64>
+// CHECK:           %[[VAL_7:.*]] = llvm.load %[[VAL_6]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT:tag_[0-9]*]]]} : !llvm.ptr<i64>
+// CHECK:           %[[VAL_8:.*]] = llvm.mul %[[VAL_5]], %[[VAL_7]]  : i64
+// CHECK:           %[[VAL_9:.*]] = llvm.add %[[VAL_8]], %[[VAL_3]]  : i64
+// CHECK:           %[[VAL_10:.*]] = llvm.getelementptr %[[VAL_0]][0, 0] : (!llvm.ptr<struct<(ptr<i32>, i64, i32, i8, i8, i8, i8, array<1 x array<3 x i64>>)>>) -> !llvm.ptr<ptr<i32>>
+// CHECK:           %[[VAL_11:.*]] = llvm.load %[[VAL_10]] {llvm.tbaa = [@__flang_tbaa::@[[BOXT]]]} : !llvm.ptr<ptr<i32>>
+// CHECK:           %[[VAL_12:.*]] = llvm.bitcast %[[VAL_11]] : !llvm.ptr<i32> to !llvm.ptr<i8>
+// CHECK:           %[[VAL_13:.*]] = llvm.getelementptr %[[VAL_12]]{{\[}}%[[VAL_9]]] : (!llvm.ptr<i8>, i64) -> !llvm.ptr<i8>
+// CHECK:           %[[VAL_14:.*]] = llvm.bitcast %[[VAL_13]] : !llvm.ptr<i8> to !llvm.ptr<i32>
+// CHECK:           llvm.return
+// CHECK:         }
+
+// CHECK-LABEL:   llvm.metadata @__flang_tbaa {
+// CHECK:           llvm.tbaa_root @[[ROOT:root_[0-9]*]] {id = "Flang Type TBAA Root"}
+// CHECK:           llvm.tbaa_type_desc @[[ANYACC:type_desc_[0-9]*]] {id = "any access", members = {<@[[ROOT]], 0>}}
+// CHECK:           llvm.tbaa_type_desc @[[ANYDACC:type_desc_[0-9]*]] {id = "any data access", members = {<@[[ANYACC]], 0>}}
+// CHECK:           llvm.tbaa_type_desc @[[BOXMEM:type_desc_[0-9]*]] {id = "descriptor member", members = {<@[[ANYACC]], 0>}}
+// CHECK:           llvm.tbaa_tag @[[BOXT]] {access_type = @[[BOXMEM]], base_type = @[[BOXMEM]], offset = 0 : i64}
+// CHECK:         }