unsafe fn size_of_bits(&self, ty: LLVMTypeRef) -> u64 {
        let layout = llvm_sys::target::LLVMGetModuleDataLayout(self.module());
        llvm_sys::target::LLVMSizeOfTypeInBits(layout, ty) as u64
    }
Returns the constant size of a type in bits.

Unlike `size_of`, this returns the size of the value at compile time.
weld/src/codegen/llvm2/mod.rs