Thread LLVMContext through the constant folding APIs, which touches a lot of files.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74844 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Analysis/ScalarEvolution.h

@@ -36,6 +36,7 @@ namespace llvm {
   class Type;
   class ScalarEvolution;
   class TargetData;
+  class LLVMContext;
 
   /// SCEV - This class represents an analyzed expression in the program.  These
   /// are opaque objects that the client is not allowed to do much with
@@ -354,6 +355,8 @@ namespace llvm {
     static char ID; // Pass identification, replacement for typeid
     ScalarEvolution();
 
+    LLVMContext* getContext() const { return Context; }
+
     /// isSCEVable - Test if values of the given type are analyzable within
     /// the SCEV framework. This primarily includes integer types, and it
     /// can optionally include pointer types if the ScalarEvolution class