diff --git a/lib/Support/APInt.cpp b/lib/Support/APInt.cpp
index 3cb75762790..d7291a18aa5 100644
--- a/lib/Support/APInt.cpp
+++ b/lib/Support/APInt.cpp
@@ -54,11 +54,11 @@ inline static unsigned getDigit(char cdigit, uint8_t radix) {
       return r;
 
     r = cdigit - 'A';
-    if (r <= radix-11)
+    if (r <= radix - 11U)
       return r + 10;
 
     r = cdigit - 'a';
-    if (r <= radix-11)
+    if (r <= radix - 11U)
       return r + 10;
   }