@@ -318,6 +318,51 @@ auto FunctionContext::GetReturnTypeInfo(TypeInFile type)
318318 return result;
319319}
320320
321+ // Given a type used for an LLVM value, return the type that we use to store
322+ // that value in memory. This is the same type unless the type is a
323+ // non-multiple-of-8 integer type, which we explicitly widen to a multiple of 8
324+ // for Clang compatibility and to make our generated IR easier for LLVM to
325+ // handle.
326+ static auto GetWidenedMemoryType (llvm::Type* type) -> llvm::Type* {
327+ if (auto * int_type = dyn_cast<llvm::IntegerType>(type)) {
328+ auto width = llvm::alignToPowerOf2 (int_type->getBitWidth (), 8 );
329+ if (width != int_type->getBitWidth ()) {
330+ return llvm::IntegerType::get (type->getContext (), width);
331+ }
332+ }
333+ return type;
334+ }
335+
336+ auto FunctionContext::LoadObject (TypeInFile type, llvm::Value* addr,
337+ llvm::Twine name) -> llvm::Value* {
338+ auto * llvm_type = GetType (type);
339+ auto * load_type = GetWidenedMemoryType (llvm_type);
340+
341+ // TODO: Include alias and alignment information.
342+ llvm::Value* value = builder ().CreateLoad (load_type, addr, name);
343+
344+ if (load_type != llvm_type) {
345+ value = builder ().CreateTrunc (value, llvm_type);
346+ }
347+ return value;
348+ }
349+
350+ auto FunctionContext::StoreObject (TypeInFile type, llvm::Value* value,
351+ llvm::Value* addr) -> void {
352+ // TODO: Include alias and alignment information.
353+ auto * llvm_type = GetType (type);
354+ CARBON_CHECK (value->getType () == llvm_type);
355+
356+ // Don't emit a store of `iN` if N is not a multiple of 8. See `LoadObject`.
357+ auto * store_type = GetWidenedMemoryType (llvm_type);
358+ if (store_type != llvm_type) {
359+ // TODO: Should we consider creating a sext if the value is signed?
360+ value = builder ().CreateZExt (value, store_type);
361+ }
362+
363+ builder ().CreateStore (value, addr);
364+ }
365+
321366auto FunctionContext::CopyValue (TypeInFile type, SemIR::InstId source_id,
322367 SemIR::InstId dest_id) -> void {
323368 switch (GetValueRepr (type).repr .kind ) {
@@ -326,7 +371,7 @@ auto FunctionContext::CopyValue(TypeInFile type, SemIR::InstId source_id,
326371 case SemIR::ValueRepr::None:
327372 break ;
328373 case SemIR::ValueRepr::Copy:
329- builder (). CreateStore ( GetValue (source_id), GetValue (dest_id));
374+ StoreObject (type, GetValue (source_id), GetValue (dest_id));
330375 break ;
331376 case SemIR::ValueRepr::Pointer:
332377 CopyObject (type, source_id, dest_id);
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