Index: lib/Target/WebAssembly/Disassembler/WebAssemblyDisassembler.cpp
===================================================================
--- lib/Target/WebAssembly/Disassembler/WebAssemblyDisassembler.cpp
+++ lib/Target/WebAssembly/Disassembler/WebAssemblyDisassembler.cpp
@@ -68,7 +68,7 @@
                                          createWebAssemblyDisassembler);
 }
 
-static uint8_t nextByte(ArrayRef<uint8_t> Bytes, uint64_t &Size) {
+static int nextByte(ArrayRef<uint8_t> Bytes, uint64_t &Size) {
   if (Size >= Bytes.size())
     return -1;
   auto V = Bytes[Size];