diff --git a/yjit/bindgen/src/main.rs b/yjit/bindgen/src/main.rs
index 7bdfdade77..f7ebb88577 100644
--- a/yjit/bindgen/src/main.rs
+++ b/yjit/bindgen/src/main.rs
@@ -66,6 +66,9 @@ fn main() {
         // From include/ruby/internal/config.h
         .allowlist_var("USE_RVARGC")
 
+        // From include/ruby/internal/special_consts.h
+        .allowlist_type("ruby_special_consts")
+
         // From include/ruby/internal/intern/string.h
         .allowlist_function("rb_utf8_str_new")
         .allowlist_function("rb_str_buf_append")
diff --git a/yjit/src/codegen.rs b/yjit/src/codegen.rs
index 196baf9689..5d144458e8 100644
--- a/yjit/src/codegen.rs
+++ b/yjit/src/codegen.rs
@@ -3296,8 +3296,7 @@ fn gen_branchunless(
         gen_direct_jump(jit, ctx, target, asm);
     } else {
         // Test if any bit (outside of the Qnil bit) is on
-        // RUBY_Qfalse  /* ...0000 0000 */
-        // RUBY_Qnil    /* ...0000 1000 */
+        // See RB_TEST()
         let not_qnil = !Qnil.as_i64();
         asm.test(val_opnd, not_qnil.into());
 
@@ -3368,7 +3367,6 @@ fn gen_branchnil(
         gen_direct_jump(jit, ctx, target, asm);
     } else {
         // Test if the value is Qnil
-        // RUBY_Qnil    /* ...0000 1000 */
         asm.cmp(val_opnd, Opnd::UImm(Qnil.into()));
         // Generate the branch instructions
         gen_branch(
diff --git a/yjit/src/cruby.rs b/yjit/src/cruby.rs
index 81db0deab3..d8dbdb4019 100644
--- a/yjit/src/cruby.rs
+++ b/yjit/src/cruby.rs
@@ -322,7 +322,8 @@ impl VALUE {
     /// Return true if the number is an immediate integer, flonum or static symbol
     fn immediate_p(self) -> bool {
         let VALUE(cval) = self;
-        (cval & 7) != 0
+        let mask = RUBY_IMMEDIATE_MASK as usize;
+        (cval & mask) != 0
     }
 
     /// Return true if the value is a Ruby immediate integer, flonum, static symbol, nil or false
@@ -333,19 +334,23 @@ impl VALUE {
     /// Return true if the value is a Ruby Fixnum (immediate-size integer)
     pub fn fixnum_p(self) -> bool {
         let VALUE(cval) = self;
-        (cval & 1) == 1
+        let flag = RUBY_FIXNUM_FLAG as usize;
+        (cval & flag) == flag
     }
 
     /// Return true if the value is an immediate Ruby floating-point number (flonum)
     pub fn flonum_p(self) -> bool {
         let VALUE(cval) = self;
-        (cval & 3) == 2
+        let mask = RUBY_FLONUM_MASK as usize;
+        let flag = RUBY_FLONUM_FLAG as usize;
+        (cval & mask) == flag
     }
 
     /// Return true for a static (non-heap) Ruby symbol
     pub fn static_sym_p(self) -> bool {
         let VALUE(cval) = self;
-        (cval & 0xff) == RUBY_SYMBOL_FLAG
+        let flag = RUBY_SYMBOL_FLAG as usize;
+        (cval & 0xff) == flag
     }
 
     /// Returns true or false depending on whether the value is nil
@@ -595,13 +600,13 @@ where
 
 // Non-idiomatic capitalization for consistency with CRuby code
 #[allow(non_upper_case_globals)]
-pub const Qfalse: VALUE = VALUE(0);
+pub const Qfalse: VALUE = VALUE(RUBY_Qfalse as usize);
 #[allow(non_upper_case_globals)]
-pub const Qnil: VALUE = VALUE(4);
+pub const Qnil: VALUE = VALUE(RUBY_Qnil as usize);
 #[allow(non_upper_case_globals)]
-pub const Qtrue: VALUE = VALUE(20);
+pub const Qtrue: VALUE = VALUE(RUBY_Qtrue as usize);
 #[allow(non_upper_case_globals)]
-pub const Qundef: VALUE = VALUE(0x24);
+pub const Qundef: VALUE = VALUE(RUBY_Qundef as usize);
 
 #[allow(unused)]
 mod manual_defs {
@@ -615,16 +620,6 @@ mod manual_defs {
 
     pub const RUBY_FIXNUM_MIN: isize = RUBY_LONG_MIN / 2;
     pub const RUBY_FIXNUM_MAX: isize = RUBY_LONG_MAX / 2;
-    pub const RUBY_FIXNUM_FLAG: usize = 0x1;
-
-    // All these are defined in include/ruby/internal/special_consts.h,
-    // in the same enum as RUBY_Qfalse, etc.
-    // Do we want to switch to using Ruby's definition of Qnil, Qfalse, etc?
-    pub const RUBY_SYMBOL_FLAG: usize = 0x0c;
-    pub const RUBY_FLONUM_FLAG: usize = 0x2;
-    pub const RUBY_FLONUM_MASK: usize = 0x3;
-    pub const RUBY_SPECIAL_SHIFT: usize = 8;
-    pub const RUBY_IMMEDIATE_MASK: usize = 0x7;
 
     // From vm_callinfo.h - uses calculation that seems to confuse bindgen
     pub const VM_CALL_ARGS_SPLAT: u32 = 1 << VM_CALL_ARGS_SPLAT_bit;
diff --git a/yjit/src/cruby_bindings.inc.rs b/yjit/src/cruby_bindings.inc.rs
index 00bade6b70..ab5db31f93 100644
--- a/yjit/src/cruby_bindings.inc.rs
+++ b/yjit/src/cruby_bindings.inc.rs
@@ -152,6 +152,17 @@ extern "C" {
 extern "C" {
     pub fn rb_method_basic_definition_p(klass: VALUE, mid: ID) -> ::std::os::raw::c_int;
 }
+pub const RUBY_Qfalse: ruby_special_consts = 0;
+pub const RUBY_Qnil: ruby_special_consts = 4;
+pub const RUBY_Qtrue: ruby_special_consts = 20;
+pub const RUBY_Qundef: ruby_special_consts = 36;
+pub const RUBY_IMMEDIATE_MASK: ruby_special_consts = 7;
+pub const RUBY_FIXNUM_FLAG: ruby_special_consts = 1;
+pub const RUBY_FLONUM_MASK: ruby_special_consts = 3;
+pub const RUBY_FLONUM_FLAG: ruby_special_consts = 2;
+pub const RUBY_SYMBOL_FLAG: ruby_special_consts = 12;
+pub const RUBY_SPECIAL_SHIFT: ruby_special_consts = 8;
+pub type ruby_special_consts = u32;
 #[repr(C)]
 pub struct RBasic {
     pub flags: VALUE,