assigned to @timurrrr

Are you working on this Timur?

Not yet.
This affects only one file of my current 500+-files target :)
Feel free to take over if you want.

If you do take over - please pay more attention to the foo mangling as half of the global mangling problem will be solved by my #13554 patch

One more possibly related test:

void foo(const unsigned int) {}
// CHECK: "\01?foo@@yaxi@Z"
// NOW: "\01?foo@@Yaxbi@Z"

More tests:

void foo(const double) {}
// CHECK: "\01?foo@@yaxn@Z"
// NOW: "\01?foo@@YAXBN@Z"

typedef double Vector[3];
void foo(const Vector) {}
// CHECK: "\01?foo@@YAXQBN@Z"
// NOW: "\01?foo@@YAXBQAN@Z"

void foo(Vector*, const Vector, const double) {}
// CHECK: "\01?foo@@YAXPAY02NQBNN@Z"
// NOW: "\01?foo@@YAXPAY02NBQANBN@Z"

void foo(Vector*) {}
// CHECK: "\01?foo@@YAXPAY02N@Z"
// NOW: "\01?foo@@YAXPAY02N@Z"
// The last one is correct now

Taking this

Good news: I think I've fixed all these issues.
I'll need to clean up the code (comments, mostly) before sending it for a review though.

Thanks for the update. I'll be happy to help review the patch once you post it.

Should be fixed by r163110.

... and added more tests in r163111.