use the narrower of Class and Module

Author: XrXr

zjit/src/hir.rs

@@ -4435,10 +4435,11 @@ impl Function {
 
     /// This puts a guard that establishes the preconditon for [Self::load_ivar]
     fn load_ivar_guard_type(&mut self, block: BlockId, recv: InsnId, recv_type: ProfiledType, state: InsnId) -> InsnId {
-        if recv_type.class().is_subclass_of(unsafe { rb_cModule }) == ClassRelationship::Subclass {
-            self.push_insn(block, Insn::GuardType { val: recv, guard_type: types::Module, state })
-        } else if recv_type.class().is_subclass_of(unsafe { rb_cClass }) == ClassRelationship::Subclass {
+        if recv_type.class().is_subclass_of(unsafe { rb_cClass }) == ClassRelationship::Subclass {
+            // Check class first since `Class < Module`
             self.push_insn(block, Insn::GuardType { val: recv, guard_type: types::Class, state })
+        } else if recv_type.class().is_subclass_of(unsafe { rb_cModule }) == ClassRelationship::Subclass {
+            self.push_insn(block, Insn::GuardType { val: recv, guard_type: types::Module, state })
         } else if recv_type.flags().is_typed_data() {
             self.push_insn(block, Insn::GuardType { val: recv, guard_type: types::TypedTData, state })
         } else {

zjit/src/hir/opt_tests.rs

@@ -7424,7 +7424,7 @@ mod hir_opt_tests {
           Jump bb3(v4)
         bb3(v6:BasicObject):
           PatchPoint SingleRactorMode
-          v17:Module = GuardType v6, Module
+          v17:Class = GuardType v6, Class
           v18:CShape = LoadField v17, :_shape_id@0x1000
           v19:CShape[0x1001] = GuardBitEquals v18, CShape(0x1001)
           PatchPoint RootBoxOnly
@@ -7459,7 +7459,7 @@ mod hir_opt_tests {
           Jump bb3(v4)
         bb3(v6:BasicObject):
           PatchPoint SingleRactorMode
-          v17:Module = GuardType v6, Module
+          v17:Class = GuardType v6, Class
           v18:CShape = LoadField v17, :_shape_id@0x1000
           v19:CShape[0x1001] = GuardBitEquals v18, CShape(0x1001)
           PatchPoint RootBoxOnly