[ConstantRange] Use const references to prevent a couple APInt copies. NFC

llvm-svn: 301694
diff --git a/llvm/lib/IR/ConstantRange.cpp b/llvm/lib/IR/ConstantRange.cpp
index 0cc38b0..a58a641 100644
--- a/llvm/lib/IR/ConstantRange.cpp
+++ b/llvm/lib/IR/ConstantRange.cpp
@@ -210,8 +210,8 @@
                                               -Other.getUnsignedMax()));
 
   if (NoWrapKind & OBO::NoSignedWrap) {
-    APInt SignedMin = Other.getSignedMin();
-    APInt SignedMax = Other.getSignedMax();
+    const APInt &SignedMin = Other.getSignedMin();
+    const APInt &SignedMax = Other.getSignedMax();
 
     if (SignedMax.isStrictlyPositive())
       Result = SubsetIntersect(