diff --git a/m4/spice-compile-warnings.m4 b/m4/spice-compile-warnings.m4
index 5a601209..2081475e 100644
--- a/m4/spice-compile-warnings.m4
+++ b/m4/spice-compile-warnings.m4
@@ -51,9 +51,6 @@ AC_DEFUN([SPICE_COMPILE_WARNINGS],[
     dontwarn="$dontwarn -Wformat-nonliteral"
     dontwarn="$dontwarn -Wfloat-equal"
     dontwarn="$dontwarn -Wdeclaration-after-statement"
-    dontwarn="$dontwarn -Wcast-qual"
-    dontwarn="$dontwarn -Wconversion"
-    dontwarn="$dontwarn -Wsign-conversion"
     dontwarn="$dontwarn -Wpacked"
     dontwarn="$dontwarn -Wunused-macros"
     dontwarn="$dontwarn -Woverlength-strings"