diff --git a/include/llvm/IR/Module.h b/include/llvm/IR/Module.h
index 6abe675..ca8a49f 100644
--- a/include/llvm/IR/Module.h
+++ b/include/llvm/IR/Module.h
@@ -229,7 +229,7 @@
   /// Returns the number of non-debug IR instructions in the module.
   /// This is equivalent to the sum of the IR instruction counts of each
   /// function contained in the module.
-  unsigned getInstructionCount();
+  unsigned getInstructionCount() const;
 
   /// Get the module's original source file name. When compiling from
   /// bitcode, this is taken from a bitcode record where it was recorded.
diff --git a/lib/IR/Module.cpp b/lib/IR/Module.cpp
index b9c3663..41666e8 100644
--- a/lib/IR/Module.cpp
+++ b/lib/IR/Module.cpp
@@ -571,9 +571,9 @@
   return cast<ConstantInt>(Val->getValue())->getZExtValue();
 }
 
-unsigned Module::getInstructionCount() {
+unsigned Module::getInstructionCount() const {
   unsigned NumInstrs = 0;
-  for (Function &F : FunctionList)
+  for (const Function &F : FunctionList)
     NumInstrs += F.getInstructionCount();
   return NumInstrs;
 }