[llvm] [Attributor] Pack out arguments into a struct (PR #119267)

[via llvm-commits]

elhewaty wrote:

@jdoerfert 
Here is the generated function, I think the code generates it perfectly for this case.
how to improve the callsite class?
```
define internal %foo_out @foo.converted(i32 %0, i32 %1) {
entry:
  %dst_ = alloca i32, align 4
  br label %entry1

entry1:                                           ; preds = %entry
  %x = xor i32 %0, 13
  %y = add i32 %1, 5
  %z = icmp sle i32 %x, %y
  br i1 %z, label %if, label %else

if:                                               ; preds = %entry1
  store i32 %x, ptr %dst_, align 4
  br label %end

else:                                             ; preds = %entry1
  store i32 %y, ptr %dst_, align 4
  br label %end

end:                                              ; preds = %else, %if
  %t = mul i32 %x, %y
  %tt = xor i32 %x, %y
  %result = icmp eq i32 %t, %tt
  %2 = load i32, ptr %dst_, align 4
  %3 = insertvalue %foo_out undef, i1 %result, 0
  %4 = insertvalue %foo_out %3, i32 %2, 1
  ret %foo_out %4
}
```
thanks.

https://github.com/llvm/llvm-project/pull/119267