diff --git a/renderdoc/driver/shaders/dxil/dxil_bytecode.cpp b/renderdoc/driver/shaders/dxil/dxil_bytecode.cpp
index 249cf880d..e7de1bf65 100644
--- a/renderdoc/driver/shaders/dxil/dxil_bytecode.cpp
+++ b/renderdoc/driver/shaders/dxil/dxil_bytecode.cpp
@@ -617,7 +617,7 @@ Program::Program(const byte *bytes, size_t length)
           std::string metastr = StringFormat::Fmt("!%u = ", (uint32_t)i);
 
           auto getMetaString = [&rootblock](uint64_t id) -> rdcstr {
-            return id ? rootblock.children[id - 1].getString() : "NULL";
+            return id ? rootblock.children[size_t(id - 1)].getString() : "NULL";
           };
 
           if(IS_KNOWN(meta.id, MetaDataRecord::STRING_OLD))
diff --git a/renderdoc/driver/shaders/dxil/llvm_decoder.cpp b/renderdoc/driver/shaders/dxil/llvm_decoder.cpp
index 2b7ab7247..f1c05c191 100644
--- a/renderdoc/driver/shaders/dxil/llvm_decoder.cpp
+++ b/renderdoc/driver/shaders/dxil/llvm_decoder.cpp
@@ -283,8 +283,8 @@ uint64_t BitcodeReader::decodeAbbrevParam(const AbbrevParam &param)
 
   switch(param.encoding)
   {
-    case AbbrevEncoding::Fixed: return b.fixed<uint64_t>(param.value);
-    case AbbrevEncoding::VBR: return b.vbr<uint64_t>(param.value);
+    case AbbrevEncoding::Fixed: return b.fixed<uint64_t>((size_t)param.value);
+    case AbbrevEncoding::VBR: return b.vbr<uint64_t>((size_t)param.value);
     case AbbrevEncoding::Char6: return b.c6();
     case AbbrevEncoding::Literal: return param.value;
     case AbbrevEncoding::Array: