RustPython
diff --git a/‎crates/codegen/src/ir.rs‎
Lines changed: 3 additions & 57 deletions b/‎crates/codegen/src/ir.rs‎
Lines changed: 3 additions & 57 deletions
diff --git a/‎crates/codegen/src/snapshots/rustpython_codegen__compile__tests__nested_double_async_with.snap‎
Lines changed: 3 additions & 3 deletions b/‎crates/codegen/src/snapshots/rustpython_codegen__compile__tests__nested_double_async_with.snap‎
Lines changed: 3 additions & 3 deletions
@@ -713,7 +713,7 @@ impl CodeInfo {
             // (or NOT_LOCAL if not from LOAD_FAST/LOAD_FAST_LOAD_FAST).
             //
             // CPython (flowgraph.c optimize_load_fast) pre-fills the stack with
-            // dummy refs for values inherited from predecessor blocks.  We take
+            // dummy refs for values inherited from predecessor blocks. We take
             // the simpler approach of aborting the optimisation for the whole
             // block on stack underflow.
             let mut stack: Vec<usize> = Vec::new();
@@ -724,62 +724,8 @@ impl CodeInfo {
                     continue;
                 };
 
-                // Decompose into (pops, pushes).
-                //
-                // stack_effect() returns pushes − pops, which is ambiguous for
-                // instructions that both pop and push (e.g. BinaryOp: effect=-1
-                // is pop 2 push 1, not pop 1 push 0).  We list those explicitly;
-                // the fallback under-pops and under-pushes, which is conservative
-                // (may miss optimisation opportunities but never miscompiles).
-                let effect = instr.stack_effect(info.arg.into());
-                let (pops, pushes) = match instr {
-                    // --- pop 2, push 1 ---
-                    Instruction::BinaryOp { .. }
-                    | Instruction::BinaryOpInplaceAddUnicode
-                    | Instruction::CompareOp { .. }
-                    | Instruction::ContainsOp(_)
-                    | Instruction::IsOp(_)
-                    | Instruction::ImportName { .. }
-                    | Instruction::FormatWithSpec => (2, 1),
-
-                    // --- pop 1, push 1 ---
-                    Instruction::UnaryInvert
-                    | Instruction::UnaryNegative
-                    | Instruction::UnaryNot
-                    | Instruction::ToBool
-                    | Instruction::GetIter
-                    | Instruction::GetAIter
-                    | Instruction::FormatSimple
-                    | Instruction::LoadFromDictOrDeref(_)
-                    | Instruction::LoadFromDictOrGlobals(_) => (1, 1),
-
-                    // LoadAttr: pop receiver, push attr.
-                    // method=true: push (method, self_or_null) → (1, 2)
-                    Instruction::LoadAttr { idx } => {
-                        let (_, is_method) =
-                            rustpython_compiler_core::bytecode::decode_load_attr_arg(
-                                idx.get(info.arg),
-                            );
-                        if is_method { (1, 2) } else { (1, 1) }
-                    }
-
-                    // --- pop 3, push 1 ---
-                    Instruction::BinarySlice => (3, 1),
-
-                    // --- variable pops, push 1 ---
-                    Instruction::Call { nargs } => (nargs.get(info.arg) as usize + 2, 1),
-                    Instruction::CallKw { nargs } => (nargs.get(info.arg) as usize + 3, 1),
-
-                    // --- conservative fallback ---
-                    // under-pops (≤ actual pops) and under-pushes (≤ actual pushes),
-                    // which keeps extra refs on the stack → marks them unconsumed →
-                    // prevents optimisation. Safe but may miss opportunities.
-                    _ => {
-                        let p = if effect < 0 { (-effect) as usize } else { 0 };
-                        let q = if effect > 0 { effect as usize } else { 0 };
-                        (p, q)
-                    }
-                };
+                let stack_effect_info = instr.stack_effect_info(info.arg.into());
+                let (pushes, pops) = (stack_effect_info.pushed(), stack_effect_info.popped());
 
                 // Pop values from stack
                 for _ in 0..pops {