[llvm] [DataFlowSanitizer] Properly add ext attributes on arguments as needed. (PR #225443)

[Jonas Paulsson via llvm-commits]

JonPsson1 wrote:

> I don't think getExtAttrForI32Param() returns the right thing for "unsigned char" arguments. I guess we need to add getExtAttrForI8Param().

I'm a little confused as it seems that all targets add zeroext on 'unsigned char f(unsigned char b)'. Would it be right to just hardcode ZExt everywhere on i8 in DataFlowSanitizer, or if not, what should getExtAttrForI8Param() do?

https://github.com/llvm/llvm-project/pull/225443