[InstCombine] Make the context instruction parameter of foldOrOfICmps a reference to discourage passing nullptr and to remove the '&' from all of the call sites. NFC

llvm-svn: 305493
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
index fd0a64a..9a52a83 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
+++ b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
@@ -449,7 +449,7 @@
 
   Value *foldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS);
   Value *foldAndOfFCmps(FCmpInst *LHS, FCmpInst *RHS);
-  Value *foldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS, Instruction *CxtI);
+  Value *foldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS, Instruction &CxtI);
   Value *foldOrOfFCmps(FCmpInst *LHS, FCmpInst *RHS);
   Value *foldXorOfICmps(ICmpInst *LHS, ICmpInst *RHS);