[clang] avoid assert due to device treated long double as double

[cchen]

Summary

Clang is currently not able to build tests in Kokkos with hip backend and it is due to the type comparison in clang::CodeGen::CodeGenModule::EmitGlobalVarDefinition (https://reviews.llvm.org/D123649).

[cchen]

clang/lib/CodeGen/CodeGenModule.cpp

4654

I only added the LangOpts that I'm familiar with but I believe there's more to add to the list.

[efriedma]

This doesn't make sense to me. If clang and LLVM disagree about the layout of a type, you are going to run into trouble. If you haven't yet, it's a matter of time.

Looking at AMDGPUTargetInfo::setAuxTarget, maybe LongDoubleFormat is somehow inconsistent with LongDoubleWidth/LongDoubleAlign?

clang/lib/CodeGen/CodeGenModule.cpp

if (!Initializer) {
       if (getLangOpts().CPlusPlus && !NeedsGlobalDtor)
         DelayedCXXInitPosition.erase(D);
 
 #ifndef NDEBUG
       CharUnits VarSize = getContext().getTypeSizeInChars(ASTTy) +
                           InitDecl->getFlexibleArrayInitChars(getContext());
       CharUnits CstSize = CharUnits::fromQuantity(
           getDataLayout().getTypeAllocSize(Init->getType()));
-      assert(VarSize == CstSize && "Emitted constant has unexpected size");
+      // 'long double' is treated as 'double' in device code
+      const BuiltinType *BType = D->getType()->getAs<BuiltinType>();
+      bool IsLongDouble = BType && BType->getKind() == BuiltinType::LongDouble;
+      bool IsDevice = getLangOpts().HIP || getLangOpts().CUDA ||
+                      getLangOpts().OpenMPIsDevice;
+      assert((VarSize == CstSize || (IsDevice && IsLongDouble)) &&
+             "Emitted constant has unexpected size");
 #endif
     }
   }
 
   llvm::Type* InitType = Init->getType();
   llvm::Constant *Entry =
       GetAddrOfGlobalVar(D, InitType, ForDefinition_t(!IsTentative));