[clang] [clang][Modules] Keep existing global definition on type mismatch in GetOrCreateLLVMGlobal (PR #223877)

[Chuanqi Xu via cfe-commits]

ChuanqiXu9 wrote:

> > This looks like a workaround to the real issue. Why can't the global be merged properly?
> 
> Can you clarify what "merge properly" means here? These globals are differing LLVM types instead of `QualType`s. I am not sure how to merge them.

I mean, these definitions should be in a redeclaration chain in AST. If it is and the CodeGen complains, I think it is CodeGen's issue. (But this is not what i know). If it is not, I think it is the problem of Sema and ASTReader.

https://github.com/llvm/llvm-project/pull/223877