diff --git a/tools/lto/LTOModule.cpp b/tools/lto/LTOModule.cpp
index 9a7d76832a1..97b58896d21 100644
--- a/tools/lto/LTOModule.cpp
+++ b/tools/lto/LTOModule.cpp
@@ -599,7 +599,7 @@ namespace {
         markGlobal(*Symbol);
     }
     virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
-                              unsigned Size , unsigned ByteAlignment) {
+                              uint64_t Size , unsigned ByteAlignment) {
       markDefined(*Symbol);
     }
     virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,