[PATCH] Add 'musttail' marker to call instructions

[Philip Reames]

On 04/09/2014 02:35 PM, Reid Kleckner wrote:
> I don't think this is worth supporting.  The frontend should be able 
> to handle this by avoiding such chains.  They already have to be 
> careful about the other rules for musttail, so this isn't much burden.
I was thinking more of the burden on optimization passes.  Say you had 
an IPO pass which wanted to change the return type of the called 
function from i32 to i1.  (Assume this is known to be legal.)  It should 
be able to just blindly insert a bitcast at the call site, not have to 
special case musttail calls.

Philip