[CIR] Correct initialization of VoidPtrPtrTy (llvm#1336)

See issue llvm#1331 for more details.

I'm not sure how to test this change; would it be enough that this does
not cause any regressions?

Author: AdUhTkJm

clang/lib/CIR/CodeGen/CIRGenModule.cpp

@@ -128,6 +128,7 @@ CIRGenModule::CIRGenModule(mlir::MLIRContext &mlirContext,
 
   // Initialize CIR pointer types cache.
   VoidPtrTy = cir::PointerType::get(&getMLIRContext(), VoidTy);
+  VoidPtrPtrTy = cir::PointerType::get(&getMLIRContext(), VoidPtrTy);
 
   FP16Ty = cir::FP16Type::get(&getMLIRContext());
   BFloat16Ty = cir::BF16Type::get(&getMLIRContext());
@@ -159,6 +160,7 @@ CIRGenModule::CIRGenModule(mlir::MLIRContext &mlirContext,
   UInt8PtrTy = builder.getPointerTo(UInt8Ty);
   UInt8PtrPtrTy = builder.getPointerTo(UInt8PtrTy);
   AllocaInt8PtrTy = UInt8PtrTy;
+  AllocaVoidPtrTy = VoidPtrTy;
   // TODO: GlobalsInt8PtrTy
   // TODO: ConstGlobalsPtrTy
   CIRAllocaAddressSpace = getTargetCIRGenInfo().getCIRAllocaAddressSpace();

clang/lib/CIR/CodeGen/CIRGenTypeCache.h

@@ -62,16 +62,12 @@ struct CIRGenTypeCache {
   cir::PointerType UInt8PtrTy;
 
   /// void** in address space 0
-  union {
-    cir::PointerType VoidPtrPtrTy;
-    cir::PointerType UInt8PtrPtrTy;
-  };
+  cir::PointerType VoidPtrPtrTy;
+  cir::PointerType UInt8PtrPtrTy;
 
   /// void* in alloca address space
-  union {
-    cir::PointerType AllocaVoidPtrTy;
-    cir::PointerType AllocaInt8PtrTy;
-  };
+  cir::PointerType AllocaVoidPtrTy;
+  cir::PointerType AllocaInt8PtrTy;
 
   /// void* in default globals address space
   //   union {