diff --git a/Ghidra/Features/Base/src/main/javacc/ghidra/app/util/cparser/C/C.jj b/Ghidra/Features/Base/src/main/javacc/ghidra/app/util/cparser/C/C.jj
index 49d6bd44d4..d990cff022 100644
--- a/Ghidra/Features/Base/src/main/javacc/ghidra/app/util/cparser/C/C.jj
+++ b/Ghidra/Features/Base/src/main/javacc/ghidra/app/util/cparser/C/C.jj
@@ -1079,11 +1079,11 @@ SKIP :
 TOKEN :
 {
     <INTEGER_LITERAL : 
-        <DECIMAL_LITERAL> (  "ull" | "ULL" | "ul" | "UL" | "ll" | "LL" | "l" | "L" | "U" | "u")? ("i")? ( ["0"-"9"] )*
+        <DECIMAL_LITERAL> (  "ull" | "ULL" | "ul" | "UL" | "ll" | "LL" | "l" | "L" | "U" | "u" | "i64" | "I64")? ("i")? ( ["0"-"9"] )*
         |
-        <HEX_LITERAL> ( "ull" | "ULL" | "ul" | "UL" | "ll" | "LL" | "l" | "L" | "U" | "u")? ("i")? ( ["0"-"9"] )*
+        <HEX_LITERAL> ( "ull" | "ULL" | "ul" | "UL" | "ll" | "LL" | "l" | "L" | "U" | "u" | "i64" | "I64")? ("i")? ( ["0"-"9"] )*
         |
-        <OCTAL_LITERAL> ( "ull" | "ULL" | "ul" | "UL" | "ll" | "LL" | "l" | "L" | "U" | "u")? ("i")? ( ["0"-"9"] )*
+        <OCTAL_LITERAL> ( "ull" | "ULL" | "ul" | "UL" | "ll" | "LL" | "l" | "L" | "U" | "u" | "i64" | "I64")? ("i")? ( ["0"-"9"] )*
     >
     |
     <#DECIMAL_LITERAL : [ "1"-"9" ] ( [ "0"-"9" ] )*>