[LLVMIR] Migrate away from PointerUnion::{is,get} (NFC)

Note that PointerUnion::{is,get} have been soft deprecated in
PointerUnion.h:

  // FIXME: Replace the uses of is(), get() and dyn_cast() with
  //        isa<T>, cast<T> and the llvm::dyn_cast<T>

I'm not touching PointerUnion::dyn_cast for now because it's a bit
complicated; we could blindly migrate it to dyn_cast_if_present, but
we should probably use dyn_cast when the operand is known to be
non-null.

Author: kazutakahirata

mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp

@@ -716,7 +716,7 @@ static void destructureIndices(Type currType, ArrayRef<GEPArg> indices,
         dynamicIndices.push_back(val);
       }
     } else {
-      rawConstantIndices.push_back(iter.get<GEPConstantIndex>());
+      rawConstantIndices.push_back(cast<GEPConstantIndex>(iter));
     }
 
     // Skip for very first iteration of this loop. First index does not index
@@ -805,7 +805,7 @@ static void printGEPIndices(OpAsmPrinter &printer, LLVM::GEPOp gepOp,
         if (Value val = llvm::dyn_cast_if_present<Value>(cst))
           printer.printOperand(val);
         else
-          printer << cst.get<IntegerAttr>().getInt();
+          printer << cast<IntegerAttr>(cst).getInt();
       });
 }
 
@@ -821,11 +821,11 @@ verifyStructIndices(Type baseGEPType, unsigned indexPos,
 
   return TypeSwitch<Type, LogicalResult>(baseGEPType)
       .Case<LLVMStructType>([&](LLVMStructType structType) -> LogicalResult {
-        if (!indices[indexPos].is<IntegerAttr>())
+        if (!isa<IntegerAttr>(indices[indexPos]))
           return emitOpError() << "expected index " << indexPos
                                << " indexing a struct to be constant";
 
-        int32_t gepIndex = indices[indexPos].get<IntegerAttr>().getInt();
+        int32_t gepIndex = cast<IntegerAttr>(indices[indexPos]).getInt();
         ArrayRef<Type> elementTypes = structType.getBody();
         if (gepIndex < 0 ||
             static_cast<size_t>(gepIndex) >= elementTypes.size())
@@ -1100,11 +1100,11 @@ CallInterfaceCallable CallOp::getCallableForCallee() {
 void CallOp::setCalleeFromCallable(CallInterfaceCallable callee) {
   // Direct call.
   if (FlatSymbolRefAttr calleeAttr = getCalleeAttr()) {
-    auto symRef = callee.get<SymbolRefAttr>();
+    auto symRef = cast<SymbolRefAttr>(callee);
     return setCalleeAttr(cast<FlatSymbolRefAttr>(symRef));
   }
   // Indirect call, callee Value is the first operand.
-  return setOperand(0, callee.get<Value>());
+  return setOperand(0, cast<Value>(callee));
 }
 
 Operation::operand_range CallOp::getArgOperands() {
@@ -1564,11 +1564,11 @@ CallInterfaceCallable InvokeOp::getCallableForCallee() {
 void InvokeOp::setCalleeFromCallable(CallInterfaceCallable callee) {
   // Direct call.
   if (FlatSymbolRefAttr calleeAttr = getCalleeAttr()) {
-    auto symRef = callee.get<SymbolRefAttr>();
+    auto symRef = cast<SymbolRefAttr>(callee);
     return setCalleeAttr(cast<FlatSymbolRefAttr>(symRef));
   }
   // Indirect call, callee Value is the first operand.
-  return setOperand(0, callee.get<Value>());
+  return setOperand(0, cast<Value>(callee));
 }
 
 Operation::operand_range InvokeOp::getArgOperands() {
@@ -3259,7 +3259,7 @@ OpFoldResult LLVM::GEPOp::fold(FoldAdaptor adaptor) {
       if (Value val = llvm::dyn_cast_if_present<Value>(existing))
         gepArgs.emplace_back(val);
       else
-        gepArgs.emplace_back(existing.get<IntegerAttr>().getInt());
+        gepArgs.emplace_back(cast<IntegerAttr>(existing).getInt());
 
       continue;
     }

mlir/lib/Dialect/LLVMIR/IR/LLVMTypes.cpp

@@ -280,7 +280,7 @@ getPointerDataLayoutEntry(DataLayoutEntryListRef params, LLVMPointerType type,
   for (DataLayoutEntryInterface entry : params) {
     if (!entry.isTypeEntry())
       continue;
-    if (cast<LLVMPointerType>(entry.getKey().get<Type>()).getAddressSpace() ==
+    if (cast<LLVMPointerType>(cast<Type>(entry.getKey())).getAddressSpace() ==
         type.getAddressSpace()) {
       currentEntry = entry.getValue();
       break;
@@ -356,7 +356,8 @@ bool LLVMPointerType::areCompatible(DataLayoutEntryListRef oldLayout,
       continue;
     uint64_t size = kDefaultPointerSizeBits;
     uint64_t abi = kDefaultPointerAlignment;
-    auto newType = llvm::cast<LLVMPointerType>(newEntry.getKey().get<Type>());
+    auto newType =
+        llvm::cast<LLVMPointerType>(llvm::cast<Type>(newEntry.getKey()));
     const auto *it =
         llvm::find_if(oldLayout, [&](DataLayoutEntryInterface entry) {
           if (auto type = llvm::dyn_cast_if_present<Type>(entry.getKey())) {
@@ -392,7 +393,7 @@ LogicalResult LLVMPointerType::verifyEntries(DataLayoutEntryListRef entries,
   for (DataLayoutEntryInterface entry : entries) {
     if (!entry.isTypeEntry())
       continue;
-    auto key = entry.getKey().get<Type>();
+    auto key = llvm::cast<Type>(entry.getKey());
     auto values = llvm::dyn_cast<DenseIntElementsAttr>(entry.getValue());
     if (!values || (values.size() != 3 && values.size() != 4)) {
       return emitError(loc)
@@ -625,11 +626,12 @@ LogicalResult LLVMStructType::verifyEntries(DataLayoutEntryListRef entries,
     if (!entry.isTypeEntry())
       continue;
 
-    auto key = llvm::cast<LLVMStructType>(entry.getKey().get<Type>());
+    auto key = llvm::cast<LLVMStructType>(llvm::cast<Type>(entry.getKey()));
     auto values = llvm::dyn_cast<DenseIntElementsAttr>(entry.getValue());
     if (!values || (values.size() != 2 && values.size() != 1)) {
       return emitError(loc)
-             << "expected layout attribute for " << entry.getKey().get<Type>()
+             << "expected layout attribute for "
+             << llvm::cast<Type>(entry.getKey())
              << " to be a dense integer elements attribute of 1 or 2 elements";
     }
     if (!values.getElementType().isInteger(64))