1 files changed, 408 insertions, 51 deletions
diff --git a/zjit/src/hir.rs b/zjit/src/hir.rs
index 17b4aad6cf..fbca1f4418 100644
--- a/zjit/src/hir.rs
+++ b/zjit/src/hir.rs
@@ -185,7 +185,9 @@ impl<'a> std::fmt::Display for InvariantPrinter<'a> {
                 write!(f, "BOPRedefined(")?;
                 match klass {
                     INTEGER_REDEFINED_OP_FLAG => write!(f, "INTEGER_REDEFINED_OP_FLAG")?,
+                    STRING_REDEFINED_OP_FLAG => write!(f, "STRING_REDEFINED_OP_FLAG")?,
                     ARRAY_REDEFINED_OP_FLAG => write!(f, "ARRAY_REDEFINED_OP_FLAG")?,
+                    HASH_REDEFINED_OP_FLAG => write!(f, "HASH_REDEFINED_OP_FLAG")?,
                     _ => write!(f, "{klass}")?,
                 }
                 write!(f, ", ")?;
@@ -201,6 +203,8 @@ impl<'a> std::fmt::Display for InvariantPrinter<'a> {
                     BOP_LE    => write!(f, "BOP_LE")?,
                     BOP_GT    => write!(f, "BOP_GT")?,
                     BOP_GE    => write!(f, "BOP_GE")?,
+                    BOP_FREEZE => write!(f, "BOP_FREEZE")?,
+                    BOP_UMINUS => write!(f, "BOP_UMINUS")?,
                     BOP_MAX    => write!(f, "BOP_MAX")?,
                     _ => write!(f, "{bop}")?,
                 }
@@ -396,7 +400,7 @@ pub enum Insn {
     /// SSA block parameter. Also used for function parameters in the function's entry block.
     Param { idx: usize },
 
-    StringCopy { val: InsnId },
+    StringCopy { val: InsnId, chilled: bool },
     StringIntern { val: InsnId },
 
     /// Put special object (VMCORE, CBASE, etc.) based on value_type
@@ -427,7 +431,7 @@ pub enum Insn {
     /// Return C `true` if `val` is `Qnil`, else `false`.
     IsNil { val: InsnId },
     Defined { op_type: usize, obj: VALUE, pushval: VALUE, v: InsnId },
-    GetConstantPath { ic: *const iseq_inline_constant_cache },
+    GetConstantPath { ic: *const iseq_inline_constant_cache, state: InsnId },
 
     /// Get a global variable named `id`
     GetGlobal { id: ID, state: InsnId },
@@ -602,7 +606,7 @@ impl<'a> std::fmt::Display for InsnPrinter<'a> {
             Insn::ArraySet { array, idx, val } => { write!(f, "ArraySet {array}, {idx}, {val}") }
             Insn::ArrayDup { val, .. } => { write!(f, "ArrayDup {val}") }
             Insn::HashDup { val, .. } => { write!(f, "HashDup {val}") }
-            Insn::StringCopy { val } => { write!(f, "StringCopy {val}") }
+            Insn::StringCopy { val, .. } => { write!(f, "StringCopy {val}") }
             Insn::Test { val } => { write!(f, "Test {val}") }
             Insn::IsNil { val } => { write!(f, "IsNil {val}") }
             Insn::Jump(target) => { write!(f, "Jump {target}") }
@@ -647,7 +651,7 @@ impl<'a> std::fmt::Display for InsnPrinter<'a> {
             Insn::GuardType { val, guard_type, .. } => { write!(f, "GuardType {val}, {}", guard_type.print(self.ptr_map)) },
             Insn::GuardBitEquals { val, expected, .. } => { write!(f, "GuardBitEquals {val}, {}", expected.print(self.ptr_map)) },
             Insn::PatchPoint(invariant) => { write!(f, "PatchPoint {}", invariant.print(self.ptr_map)) },
-            Insn::GetConstantPath { ic } => { write!(f, "GetConstantPath {:p}", self.ptr_map.map_ptr(ic)) },
+            Insn::GetConstantPath { ic, .. } => { write!(f, "GetConstantPath {:p}", self.ptr_map.map_ptr(ic)) },
             Insn::CCall { cfun, args, name, return_type: _, elidable: _ } => {
                 write!(f, "CCall {}@{:p}", name.contents_lossy(), self.ptr_map.map_ptr(cfun))?;
                 for arg in args {
@@ -978,7 +982,7 @@ impl Function {
                     }
                 },
             Return { val } => Return { val: find!(*val) },
-            StringCopy { val } => StringCopy { val: find!(*val) },
+            StringCopy { val, chilled } => StringCopy { val: find!(*val), chilled: *chilled },
             StringIntern { val } => StringIntern { val: find!(*val) },
             Test { val } => Test { val: find!(*val) },
             &IsNil { val } => IsNil { val: find!(val) },
@@ -1250,6 +1254,38 @@ impl Function {
         }
     }
 
+    fn rewrite_if_frozen(&mut self, block: BlockId, orig_insn_id: InsnId, self_val: InsnId, klass: u32, bop: u32) {
+        let self_type = self.type_of(self_val);
+        if let Some(obj) = self_type.ruby_object() {
+            if obj.is_frozen() {
+                self.push_insn(block, Insn::PatchPoint(Invariant::BOPRedefined { klass, bop }));
+                self.make_equal_to(orig_insn_id, self_val);
+                return;
+            }
+        }
+        self.push_insn_id(block, orig_insn_id);
+    }
+
+    fn try_rewrite_freeze(&mut self, block: BlockId, orig_insn_id: InsnId, self_val: InsnId) {
+        if self.is_a(self_val, types::StringExact) {
+            self.rewrite_if_frozen(block, orig_insn_id, self_val, STRING_REDEFINED_OP_FLAG, BOP_FREEZE);
+        } else if self.is_a(self_val, types::ArrayExact) {
+            self.rewrite_if_frozen(block, orig_insn_id, self_val, ARRAY_REDEFINED_OP_FLAG, BOP_FREEZE);
+        } else if self.is_a(self_val, types::HashExact) {
+            self.rewrite_if_frozen(block, orig_insn_id, self_val, HASH_REDEFINED_OP_FLAG, BOP_FREEZE);
+        } else {
+            self.push_insn_id(block, orig_insn_id);
+        }
+    }
+
+    fn try_rewrite_uminus(&mut self, block: BlockId, orig_insn_id: InsnId, self_val: InsnId) {
+        if self.is_a(self_val, types::StringExact) {
+            self.rewrite_if_frozen(block, orig_insn_id, self_val, STRING_REDEFINED_OP_FLAG, BOP_UMINUS);
+        } else {
+            self.push_insn_id(block, orig_insn_id);
+        }
+    }
+
     /// Rewrite SendWithoutBlock opcodes into SendWithoutBlockDirect opcodes if we know the target
     /// ISEQ statically. This removes run-time method lookups and opens the door for inlining.
     fn optimize_direct_sends(&mut self) {
@@ -1280,6 +1316,10 @@ impl Function {
                         self.try_rewrite_fixnum_op(block, insn_id, &|left, right| Insn::FixnumGt { left, right }, BOP_GT, self_val, args[0], state),
                     Insn::SendWithoutBlock { self_val, call_info: CallInfo { method_name }, args, state, .. } if method_name == ">=" && args.len() == 1 =>
                         self.try_rewrite_fixnum_op(block, insn_id, &|left, right| Insn::FixnumGe { left, right }, BOP_GE, self_val, args[0], state),
+                    Insn::SendWithoutBlock { self_val, call_info: CallInfo { method_name }, args, .. } if method_name == "freeze" && args.len() == 0 =>
+                        self.try_rewrite_freeze(block, insn_id, self_val),
+                    Insn::SendWithoutBlock { self_val, call_info: CallInfo { method_name }, args, .. } if method_name == "-@" && args.len() == 0 =>
+                        self.try_rewrite_uminus(block, insn_id, self_val),
                     Insn::SendWithoutBlock { mut self_val, call_info, cd, args, state } => {
                         let frame_state = self.frame_state(state);
                         let (klass, guard_equal_to) = if let Some(klass) = self.type_of(self_val).runtime_exact_ruby_class() {
@@ -1315,7 +1355,7 @@ impl Function {
                         let send_direct = self.push_insn(block, Insn::SendWithoutBlockDirect { self_val, call_info, cd, cme, iseq, args, state });
                         self.make_equal_to(insn_id, send_direct);
                     }
-                    Insn::GetConstantPath { ic } => {
+                    Insn::GetConstantPath { ic, .. } => {
                         let idlist: *const ID = unsafe { (*ic).segments };
                         let ice = unsafe { (*ic).entry };
                         if ice.is_null() {
@@ -1602,10 +1642,14 @@ impl Function {
             if necessary[insn_id.0] { continue; }
             necessary[insn_id.0] = true;
             match self.find(insn_id) {
-                Insn::Const { .. } | Insn::Param { .. }
-                | Insn::PatchPoint(..) | Insn::GetConstantPath { .. }
+                Insn::Const { .. }
+                | Insn::Param { .. }
+                | Insn::PatchPoint(..)
                 | Insn::PutSpecialObject { .. } =>
                     {}
+                Insn::GetConstantPath { ic: _, state } => {
+                    worklist.push_back(state);
+                }
                 Insn::ArrayMax { elements, state }
                 | Insn::NewArray { elements, state } => {
                     worklist.extend(elements);
@@ -1623,7 +1667,7 @@ impl Function {
                     worklist.push_back(high);
                     worklist.push_back(state);
                 }
-                Insn::StringCopy { val }
+                Insn::StringCopy { val, .. }
                 | Insn::StringIntern { val }
                 | Insn::Return { val }
                 | Insn::Defined { v: val, .. }
@@ -2142,10 +2186,14 @@ pub fn iseq_to_hir(iseq: *const rb_iseq_t) -> Result<Function, ParseError> {
                     let value_type = SpecialObjectType::from(get_arg(pc, 0).as_u32());
                     state.stack_push(fun.push_insn(block, Insn::PutSpecialObject { value_type }));
                 }
-                YARVINSN_putstring | YARVINSN_putchilledstring => {
-                    // TODO(max): Do something different for chilled string
+                YARVINSN_putstring => {
+                    let val = fun.push_insn(block, Insn::Const { val: Const::Value(get_arg(pc, 0)) });
+                    let insn_id = fun.push_insn(block, Insn::StringCopy { val, chilled: false });
+                    state.stack_push(insn_id);
+                }
+                YARVINSN_putchilledstring => {
                     let val = fun.push_insn(block, Insn::Const { val: Const::Value(get_arg(pc, 0)) });
-                    let insn_id = fun.push_insn(block, Insn::StringCopy { val });
+                    let insn_id = fun.push_insn(block, Insn::StringCopy { val, chilled: true });
                     state.stack_push(insn_id);
                 }
                 YARVINSN_putself => { state.stack_push(self_param); }
@@ -2265,7 +2313,8 @@ pub fn iseq_to_hir(iseq: *const rb_iseq_t) -> Result<Function, ParseError> {
                 }
                 YARVINSN_opt_getconstant_path => {
                     let ic = get_arg(pc, 0).as_ptr();
-                    state.stack_push(fun.push_insn(block, Insn::GetConstantPath { ic }));
+                    let snapshot = fun.push_insn(block, Insn::Snapshot { state: exit_state });
+                    state.stack_push(fun.push_insn(block, Insn::GetConstantPath { ic, state: snapshot }));
                 }
                 YARVINSN_branchunless => {
                     let offset = get_arg(pc, 0).as_i64();
@@ -2417,6 +2466,34 @@ pub fn iseq_to_hir(iseq: *const rb_iseq_t) -> Result<Function, ParseError> {
                     let send = fun.push_insn(block, Insn::SendWithoutBlock { self_val: recv, call_info: CallInfo { method_name }, cd, args, state: exit_id });
                     state.stack_push(send);
                 }
+                YARVINSN_opt_hash_freeze |
+                YARVINSN_opt_ary_freeze |
+                YARVINSN_opt_str_freeze |
+                YARVINSN_opt_str_uminus => {
+                    // NB: these instructions have the recv for the call at get_arg(0)
+                    let cd: *const rb_call_data = get_arg(pc, 1).as_ptr();
+                    let call_info = unsafe { rb_get_call_data_ci(cd) };
+                    if unknown_call_type(unsafe { rb_vm_ci_flag(call_info) }) {
+                        // Unknown call type; side-exit into the interpreter
+                        let exit_id = fun.push_insn(block, Insn::Snapshot { state: exit_state });
+                        fun.push_insn(block, Insn::SideExit { state: exit_id });
+                        break;  // End the block
+                    }
+                    let argc = unsafe { vm_ci_argc((*cd).ci) };
+                    let name = insn_name(opcode as usize);
+                    assert_eq!(0, argc, "{name} should not have args");
+                    let args = vec![];
+
+                    let method_name = unsafe {
+                        let mid = rb_vm_ci_mid(call_info);
+                        mid.contents_lossy().into_owned()
+                    };
+
+                    let exit_id = fun.push_insn(block, Insn::Snapshot { state: exit_state });
+                    let recv = fun.push_insn(block, Insn::Const { val: Const::Value(get_arg(pc, 0)) });
+                    let send = fun.push_insn(block, Insn::SendWithoutBlock { self_val: recv, call_info: CallInfo { method_name }, cd, args, state: exit_id });
+                    state.stack_push(send);
+                }
 
                 YARVINSN_leave => {
                     fun.push_insn(block, Insn::Return { val: state.stack_pop()? });
@@ -3095,6 +3172,62 @@ mod tests {
     }
 
     #[test]
+    fn test_opt_hash_freeze() {
+        eval("
+            def test = {}.freeze
+        ");
+        assert_method_hir_with_opcode("test", YARVINSN_opt_hash_freeze, expect![[r#"
+            fn test:
+            bb0(v0:BasicObject):
+              v3:HashExact[VALUE(0x1000)] = Const Value(VALUE(0x1000))
+              v4:BasicObject = SendWithoutBlock v3, :freeze
+              Return v4
+        "#]]);
+    }
+
+    #[test]
+    fn test_opt_ary_freeze() {
+        eval("
+            def test = [].freeze
+        ");
+        assert_method_hir_with_opcode("test", YARVINSN_opt_ary_freeze, expect![[r#"
+            fn test:
+            bb0(v0:BasicObject):
+              v3:ArrayExact[VALUE(0x1000)] = Const Value(VALUE(0x1000))
+              v4:BasicObject = SendWithoutBlock v3, :freeze
+              Return v4
+        "#]]);
+    }
+
+    #[test]
+    fn test_opt_str_freeze() {
+        eval("
+            def test = ''.freeze
+        ");
+        assert_method_hir_with_opcode("test", YARVINSN_opt_str_freeze, expect![[r#"
+            fn test:
+            bb0(v0:BasicObject):
+              v3:StringExact[VALUE(0x1000)] = Const Value(VALUE(0x1000))
+              v4:BasicObject = SendWithoutBlock v3, :freeze
+              Return v4
+        "#]]);
+    }
+
+    #[test]
+    fn test_opt_str_uminus() {
+        eval("
+            def test = -''
+        ");
+        assert_method_hir_with_opcode("test", YARVINSN_opt_str_uminus, expect![[r#"
+            fn test:
+            bb0(v0:BasicObject):
+              v3:StringExact[VALUE(0x1000)] = Const Value(VALUE(0x1000))
+              v4:BasicObject = SendWithoutBlock v3, :-@
+              Return v4
+        "#]]);
+    }
+
+    #[test]
     fn test_setlocal_getlocal() {
         eval("
             def test
@@ -3617,14 +3750,14 @@ mod tests {
         assert_method_hir_with_opcode("test", YARVINSN_opt_new, expect![[r#"
             fn test:
             bb0(v0:BasicObject):
-              v2:BasicObject = GetConstantPath 0x1000
-              v3:NilClassExact = Const Value(nil)
-              Jump bb1(v0, v3, v2)
-            bb1(v5:BasicObject, v6:NilClassExact, v7:BasicObject):
-              v10:BasicObject = SendWithoutBlock v7, :new
-              Jump bb2(v5, v10, v6)
-            bb2(v12:BasicObject, v13:BasicObject, v14:NilClassExact):
-              Return v13
+              v3:BasicObject = GetConstantPath 0x1000
+              v4:NilClassExact = Const Value(nil)
+              Jump bb1(v0, v4, v3)
+            bb1(v6:BasicObject, v7:NilClassExact, v8:BasicObject):
+              v11:BasicObject = SendWithoutBlock v8, :new
+              Jump bb2(v6, v11, v7)
+            bb2(v13:BasicObject, v14:BasicObject, v15:NilClassExact):
+              Return v14
         "#]]);
     }
 
@@ -5027,9 +5160,9 @@ mod opt_tests {
         assert_optimized_method_hir("test", expect![[r#"
             fn test:
             bb0(v0:BasicObject):
-              v2:BasicObject = GetConstantPath 0x1000
-              v3:Fixnum[5] = Const Value(5)
-              Return v3
+              v3:BasicObject = GetConstantPath 0x1000
+              v4:Fixnum[5] = Const Value(5)
+              Return v4
         "#]]);
     }
 
@@ -5098,8 +5231,8 @@ mod opt_tests {
               PatchPoint SingleRactorMode
               PatchPoint StableConstantNames(0x1000, M)
               PatchPoint MethodRedefined(Module@0x1008, name@0x1010)
-              v6:Fixnum[1] = Const Value(1)
-              Return v6
+              v7:Fixnum[1] = Const Value(1)
+              Return v7
         "#]]);
     }
 
@@ -5216,8 +5349,8 @@ mod opt_tests {
         assert_optimized_method_hir("test", expect![[r#"
             fn test:
             bb0(v0:BasicObject):
-              v2:BasicObject = GetConstantPath 0x1000
-              Return v2
+              v3:BasicObject = GetConstantPath 0x1000
+              Return v3
         "#]]);
     }
 
@@ -5231,8 +5364,8 @@ mod opt_tests {
         assert_optimized_method_hir("test", expect![[r#"
             fn test:
             bb0(v0:BasicObject):
-              v2:BasicObject = GetConstantPath 0x1000
-              Return v2
+              v3:BasicObject = GetConstantPath 0x1000
+              Return v3
         "#]]);
     }
 
@@ -5247,8 +5380,8 @@ mod opt_tests {
             bb0(v0:BasicObject):
               PatchPoint SingleRactorMode
               PatchPoint StableConstantNames(0x1000, Kernel)
-              v6:BasicObject[VALUE(0x1008)] = Const Value(VALUE(0x1008))
-              Return v6
+              v7:BasicObject[VALUE(0x1008)] = Const Value(VALUE(0x1008))
+              Return v7
         "#]]);
     }
 
@@ -5269,8 +5402,8 @@ mod opt_tests {
             bb0(v0:BasicObject):
               PatchPoint SingleRactorMode
               PatchPoint StableConstantNames(0x1000, Foo::Bar::C)
-              v6:BasicObject[VALUE(0x1008)] = Const Value(VALUE(0x1008))
-              Return v6
+              v7:BasicObject[VALUE(0x1008)] = Const Value(VALUE(0x1008))
+              Return v7
         "#]]);
     }
 
@@ -5286,14 +5419,14 @@ mod opt_tests {
             bb0(v0:BasicObject):
               PatchPoint SingleRactorMode
               PatchPoint StableConstantNames(0x1000, C)
-              v19:BasicObject[VALUE(0x1008)] = Const Value(VALUE(0x1008))
-              v3:NilClassExact = Const Value(nil)
-              Jump bb1(v0, v3, v19)
-            bb1(v5:BasicObject, v6:NilClassExact, v7:BasicObject[VALUE(0x1008)]):
-              v10:BasicObject = SendWithoutBlock v7, :new
-              Jump bb2(v5, v10, v6)
-            bb2(v12:BasicObject, v13:BasicObject, v14:NilClassExact):
-              Return v13
+              v20:BasicObject[VALUE(0x1008)] = Const Value(VALUE(0x1008))
+              v4:NilClassExact = Const Value(nil)
+              Jump bb1(v0, v4, v20)
+            bb1(v6:BasicObject, v7:NilClassExact, v8:BasicObject[VALUE(0x1008)]):
+              v11:BasicObject = SendWithoutBlock v8, :new
+              Jump bb2(v6, v11, v7)
+            bb2(v13:BasicObject, v14:BasicObject, v15:NilClassExact):
+              Return v14
         "#]]);
     }
 
@@ -5313,15 +5446,15 @@ mod opt_tests {
             bb0(v0:BasicObject):
               PatchPoint SingleRactorMode
               PatchPoint StableConstantNames(0x1000, C)
-              v21:BasicObject[VALUE(0x1008)] = Const Value(VALUE(0x1008))
-              v3:NilClassExact = Const Value(nil)
-              v4:Fixnum[1] = Const Value(1)
-              Jump bb1(v0, v3, v21, v4)
-            bb1(v6:BasicObject, v7:NilClassExact, v8:BasicObject[VALUE(0x1008)], v9:Fixnum[1]):
-              v12:BasicObject = SendWithoutBlock v8, :new, v9
-              Jump bb2(v6, v12, v7)
-            bb2(v14:BasicObject, v15:BasicObject, v16:NilClassExact):
-              Return v15
+              v22:BasicObject[VALUE(0x1008)] = Const Value(VALUE(0x1008))
+              v4:NilClassExact = Const Value(nil)
+              v5:Fixnum[1] = Const Value(1)
+              Jump bb1(v0, v4, v22, v5)
+            bb1(v7:BasicObject, v8:NilClassExact, v9:BasicObject[VALUE(0x1008)], v10:Fixnum[1]):
+              v13:BasicObject = SendWithoutBlock v9, :new, v10
+              Jump bb2(v7, v13, v8)
+            bb2(v15:BasicObject, v16:BasicObject, v17:NilClassExact):
+              Return v16
         "#]]);
     }
 
@@ -5381,4 +5514,228 @@ mod opt_tests {
               Return v2
         "#]]);
     }
+
+    #[test]
+    fn test_elide_freeze_with_frozen_hash() {
+        eval("
+            def test = {}.freeze
+        ");
+        assert_optimized_method_hir("test",  expect![[r#"
+            fn test:
+            bb0(v0:BasicObject):
+              v3:HashExact[VALUE(0x1000)] = Const Value(VALUE(0x1000))
+              PatchPoint BOPRedefined(HASH_REDEFINED_OP_FLAG, BOP_FREEZE)
+              Return v3
+        "#]]);
+    }
+
+    #[test]
+    fn test_elide_freeze_with_refrozen_hash() {
+        eval("
+            def test = {}.freeze.freeze
+        ");
+        assert_optimized_method_hir("test",  expect![[r#"
+            fn test:
+            bb0(v0:BasicObject):
+              v3:HashExact[VALUE(0x1000)] = Const Value(VALUE(0x1000))
+              PatchPoint BOPRedefined(HASH_REDEFINED_OP_FLAG, BOP_FREEZE)
+              PatchPoint BOPRedefined(HASH_REDEFINED_OP_FLAG, BOP_FREEZE)
+              Return v3
+        "#]]);
+    }
+
+    #[test]
+    fn test_no_elide_freeze_with_unfrozen_hash() {
+        eval("
+            def test = {}.dup.freeze
+        ");
+        assert_optimized_method_hir("test",  expect![[r#"
+            fn test:
+            bb0(v0:BasicObject):
+              v3:HashExact = NewHash
+              v5:BasicObject = SendWithoutBlock v3, :dup
+              v7:BasicObject = SendWithoutBlock v5, :freeze
+              Return v7
+        "#]]);
+    }
+
+    #[test]
+    fn test_no_elide_freeze_hash_with_args() {
+        eval("
+            def test = {}.freeze(nil)
+        ");
+        assert_optimized_method_hir("test",  expect![[r#"
+            fn test:
+            bb0(v0:BasicObject):
+              v3:HashExact = NewHash
+              v4:NilClassExact = Const Value(nil)
+              v6:BasicObject = SendWithoutBlock v3, :freeze, v4
+              Return v6
+        "#]]);
+    }
+
+    #[test]
+    fn test_elide_freeze_with_frozen_ary() {
+        eval("
+            def test = [].freeze
+        ");
+        assert_optimized_method_hir("test",  expect![[r#"
+            fn test:
+            bb0(v0:BasicObject):
+              v3:ArrayExact[VALUE(0x1000)] = Const Value(VALUE(0x1000))
+              PatchPoint BOPRedefined(ARRAY_REDEFINED_OP_FLAG, BOP_FREEZE)
+              Return v3
+        "#]]);
+    }
+
+    #[test]
+    fn test_elide_freeze_with_refrozen_ary() {
+        eval("
+            def test = [].freeze.freeze
+        ");
+        assert_optimized_method_hir("test",  expect![[r#"
+            fn test:
+            bb0(v0:BasicObject):
+              v3:ArrayExact[VALUE(0x1000)] = Const Value(VALUE(0x1000))
+              PatchPoint BOPRedefined(ARRAY_REDEFINED_OP_FLAG, BOP_FREEZE)
+              PatchPoint BOPRedefined(ARRAY_REDEFINED_OP_FLAG, BOP_FREEZE)
+              Return v3
+        "#]]);
+    }
+
+    #[test]
+    fn test_no_elide_freeze_with_unfrozen_ary() {
+        eval("
+            def test = [].dup.freeze
+        ");
+        assert_optimized_method_hir("test",  expect![[r#"
+            fn test:
+            bb0(v0:BasicObject):
+              v3:ArrayExact = NewArray
+              v5:BasicObject = SendWithoutBlock v3, :dup
+              v7:BasicObject = SendWithoutBlock v5, :freeze
+              Return v7
+        "#]]);
+    }
+
+    #[test]
+    fn test_no_elide_freeze_ary_with_args() {
+        eval("
+            def test = [].freeze(nil)
+        ");
+        assert_optimized_method_hir("test",  expect![[r#"
+            fn test:
+            bb0(v0:BasicObject):
+              v3:ArrayExact = NewArray
+              v4:NilClassExact = Const Value(nil)
+              v6:BasicObject = SendWithoutBlock v3, :freeze, v4
+              Return v6
+        "#]]);
+    }
+
+    #[test]
+    fn test_elide_freeze_with_frozen_str() {
+        eval("
+            def test = ''.freeze
+        ");
+        assert_optimized_method_hir("test",  expect![[r#"
+            fn test:
+            bb0(v0:BasicObject):
+              v3:StringExact[VALUE(0x1000)] = Const Value(VALUE(0x1000))
+              PatchPoint BOPRedefined(STRING_REDEFINED_OP_FLAG, BOP_FREEZE)
+              Return v3
+        "#]]);
+    }
+
+    #[test]
+    fn test_elide_freeze_with_refrozen_str() {
+        eval("
+            def test = ''.freeze.freeze
+        ");
+        assert_optimized_method_hir("test",  expect![[r#"
+            fn test:
+            bb0(v0:BasicObject):
+              v3:StringExact[VALUE(0x1000)] = Const Value(VALUE(0x1000))
+              PatchPoint BOPRedefined(STRING_REDEFINED_OP_FLAG, BOP_FREEZE)
+              PatchPoint BOPRedefined(STRING_REDEFINED_OP_FLAG, BOP_FREEZE)
+              Return v3
+        "#]]);
+    }
+
+    #[test]
+    fn test_no_elide_freeze_with_unfrozen_str() {
+        eval("
+            def test = ''.dup.freeze
+        ");
+        assert_optimized_method_hir("test",  expect![[r#"
+            fn test:
+            bb0(v0:BasicObject):
+              v2:StringExact[VALUE(0x1000)] = Const Value(VALUE(0x1000))
+              v3:StringExact = StringCopy v2
+              v5:BasicObject = SendWithoutBlock v3, :dup
+              v7:BasicObject = SendWithoutBlock v5, :freeze
+              Return v7
+        "#]]);
+    }
+
+    #[test]
+    fn test_no_elide_freeze_str_with_args() {
+        eval("
+            def test = ''.freeze(nil)
+        ");
+        assert_optimized_method_hir("test",  expect![[r#"
+            fn test:
+            bb0(v0:BasicObject):
+              v2:StringExact[VALUE(0x1000)] = Const Value(VALUE(0x1000))
+              v3:StringExact = StringCopy v2
+              v4:NilClassExact = Const Value(nil)
+              v6:BasicObject = SendWithoutBlock v3, :freeze, v4
+              Return v6
+        "#]]);
+    }
+
+    #[test]
+    fn test_elide_uminus_with_frozen_str() {
+        eval("
+            def test = -''
+        ");
+        assert_optimized_method_hir("test",  expect![[r#"
+            fn test:
+            bb0(v0:BasicObject):
+              v3:StringExact[VALUE(0x1000)] = Const Value(VALUE(0x1000))
+              PatchPoint BOPRedefined(STRING_REDEFINED_OP_FLAG, BOP_UMINUS)
+              Return v3
+        "#]]);
+    }
+
+    #[test]
+    fn test_elide_uminus_with_refrozen_str() {
+        eval("
+            def test = -''.freeze
+        ");
+        assert_optimized_method_hir("test",  expect![[r#"
+            fn test:
+            bb0(v0:BasicObject):
+              v3:StringExact[VALUE(0x1000)] = Const Value(VALUE(0x1000))
+              PatchPoint BOPRedefined(STRING_REDEFINED_OP_FLAG, BOP_FREEZE)
+              PatchPoint BOPRedefined(STRING_REDEFINED_OP_FLAG, BOP_UMINUS)
+              Return v3
+        "#]]);
+    }
+
+    #[test]
+    fn test_no_elide_uminus_with_unfrozen_str() {
+        eval("
+            def test = -''.dup
+        ");
+        assert_optimized_method_hir("test",  expect![[r#"
+            fn test:
+            bb0(v0:BasicObject):
+              v2:StringExact[VALUE(0x1000)] = Const Value(VALUE(0x1000))
+              v3:StringExact = StringCopy v2
+              v5:BasicObject = SendWithoutBlock v3, :dup
+              v7:BasicObject = SendWithoutBlock v5, :-@
+              Return v7
+        "#]]);
+    }
 }