[clang] added regcall struct by reg support (PR #95257)

[via cfe-commits]

mahesh-attarde wrote:

@erichkeane 
Regcall spec has mentioned allocation strategy that is chunk based.
Do you know why currently clang does not do that ? is there different version of regcall spec it follows?
Also if we add new regcall struct implementation, would that break binaries across clang version?


https://github.com/llvm/llvm-project/pull/95257