Index: llvm/lib/Support/xxhash.cpp
===================================================================
--- llvm/lib/Support/xxhash.cpp
+++ llvm/lib/Support/xxhash.cpp
@@ -119,7 +119,7 @@
   }
 
   while (P < BEnd) {
-    H64 ^= (*P) * PRIME64_5;
+    H64 ^= uint8_t(*P) * PRIME64_5;
     H64 = rotl64(H64, 11) * PRIME64_1;
     P++;
   }