Implement a new optimization in the inliner: if inlining multiple

calls into a function and if the calls bring in arrays, try to merge
them together to reduce stack size.  For example, in the testcase
we'd previously end up with 4 allocas, now we end up with 2 allocas.

As described in the comments, this is not really the ideal solution
to this problem, but it is surprisingly effective.  For example, on
176.gcc, we end up eliminating 67 arrays at "gccas" time and another
24 at "llvm-ld" time.

One piece of concern that I didn't look into: at -O0 -g with
forced inlining this will almost certainly result in worse debug
info.  I think this is acceptable though given that this is a case
of "debugging optimized code", and we don't want debug info to
prevent the optimizer from doing things anyway.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80215 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Transforms/IPO/InlinerPass.h

@@ -79,10 +79,6 @@ private:
   /// shouldInline - Return true if the inliner should attempt to
   /// inline at the given CallSite.
   bool shouldInline(CallSite CS);
-  
-  bool InlineCallIfPossible(CallSite CS, CallGraph &CG,
-                            const SmallPtrSet<Function*, 8> &SCCFunctions,
-                            const TargetData *TD);
 };
 
 } // End llvm namespace