diff --git a/llvm/test/tools/llvm-rc/codepage.test b/llvm/test/tools/llvm-rc/codepage.test
--- a/llvm/test/tools/llvm-rc/codepage.test
+++ b/llvm/test/tools/llvm-rc/codepage.test
@@ -4,6 +4,8 @@
 ; RUN: llvm-readobj %t.utf8.res | FileCheck %s --check-prefix=UTF8
 ; RUN: llvm-windres --no-preprocess --codepage 65001 %p/Inputs/utf8.rc %t.utf8.res
 ; RUN: llvm-readobj %t.utf8.res | FileCheck %s --check-prefix=UTF8
+; RUN: llvm-windres --no-preprocess --codepage 0xfde9 %p/Inputs/utf8.rc %t.utf8.res
+; RUN: llvm-readobj %t.utf8.res | FileCheck %s --check-prefix=UTF8
 
 ; UTF8:      Resource type (int): STRINGTABLE (ID 6)
 ; UTF8-NEXT: Resource name (int): 1
diff --git a/llvm/test/tools/llvm-rc/language.test b/llvm/test/tools/llvm-rc/language.test
--- a/llvm/test/tools/llvm-rc/language.test
+++ b/llvm/test/tools/llvm-rc/language.test
@@ -6,6 +6,8 @@
 ; RUN: llvm-readobj %t.res | FileCheck %s
 ; RUN: llvm-windres --no-preprocess --language 40A %p/Inputs/language.rc %t.res
 ; RUN: llvm-readobj %t.res | FileCheck %s
+; RUN: llvm-windres --no-preprocess -l 0x40A %p/Inputs/language.rc %t.res
+; RUN: llvm-readobj %t.res | FileCheck %s
 
 ; CHECK:      Resource name (int): 1
 ; CHECK-NEXT: Data version:
diff --git a/llvm/tools/llvm-rc/llvm-rc.cpp b/llvm/tools/llvm-rc/llvm-rc.cpp
--- a/llvm/tools/llvm-rc/llvm-rc.cpp
+++ b/llvm/tools/llvm-rc/llvm-rc.cpp
@@ -476,13 +476,14 @@
   Opts.Params.CodePage = CpWin1252; // Different default
   if (InputArgs.hasArg(WINDRES_codepage)) {
     if (InputArgs.getLastArgValue(WINDRES_codepage)
-            .getAsInteger(10, Opts.Params.CodePage))
+            .getAsInteger(0, Opts.Params.CodePage))
       fatalError("Invalid code page: " +
                  InputArgs.getLastArgValue(WINDRES_codepage));
   }
   if (InputArgs.hasArg(WINDRES_language)) {
-    if (InputArgs.getLastArgValue(WINDRES_language)
-            .getAsInteger(16, Opts.LangId))
+    StringRef Val = InputArgs.getLastArgValue(WINDRES_language);
+    Val.consume_front_insensitive("0x");
+    if (Val.getAsInteger(16, Opts.LangId))
       fatalError("Invalid language id: " +
                  InputArgs.getLastArgValue(WINDRES_language));
   }
@@ -565,7 +566,9 @@
   }
   Opts.AppendNull = InputArgs.hasArg(OPT_add_null);
   if (InputArgs.hasArg(OPT_lang_id)) {
-    if (InputArgs.getLastArgValue(OPT_lang_id).getAsInteger(16, Opts.LangId))
+    StringRef Val = InputArgs.getLastArgValue(OPT_lang_id);
+    Val.consume_front_insensitive("0x");
+    if (Val.getAsInteger(16, Opts.LangId))
       fatalError("Invalid language id: " +
                  InputArgs.getLastArgValue(OPT_lang_id));
   }