[C++] Tail Call op Articles

LLVM Tail call optimization
stackoverflow : LLVM tail call optimization
http://en.wikipedia.org/wiki/Tail_call

Tail call optimization, callee reusing the stack of the caller, is currently supported on x86/x86-64 and PowerPC.

It is performed if:

• Caller and callee have the calling convention fastcc, cc 10 (GHC calling convention) or cc 11 (HiPE calling convention). 
• The call is a tail call - in tail position (ret immediately follows call and ret uses value of call or is void). 
• Option -tailcallopt is enabled. 
• Platform-specific constraints are met. 
• x86/x86-64 constraints: 
• No variable argument lists are used. 
• On x86-64 when generating GOT/PIC code only module-local calls (visibility = hidden or protected) are supported.