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Fold const bool with unary not #7357

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Merged
youknowone merged 2 commits into from
Mar 5, 2026
Merged

Fold const bool with unary not #7357

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a7272a1
Fold const bool with unary not
moreal Mar 5, 2026
573fe02
Fold unnecessary TO_BOOL
moreal Mar 5, 2026
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21 changes: 21 additions & 0 deletions crates/codegen/src/compile.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -9069,6 +9069,18 @@ mod tests {

fn compile_exec(source: &str) -> CodeObject {
let opts = CompileOpts::default();
compile_exec_with_options(source, opts)
}

fn compile_exec_optimized(source: &str) -> CodeObject {
let opts = CompileOpts {
optimize: 1,
..CompileOpts::default()
};
compile_exec_with_options(source, opts)
}

fn compile_exec_with_options(source: &str, opts: CompileOpts) -> CodeObject {
let source_file = SourceFileBuilder::new("source_path", source).finish();
let parsed = ruff_python_parser::parse(
source_file.source_text(),
Expand Down Expand Up @@ -9137,6 +9149,15 @@ x = Test() and False or False
));
}

#[test]
fn test_const_bool_not_op() {
assert_dis_snapshot!(compile_exec_optimized(
"\
x = not True
"
));
}

#[test]
fn test_nested_double_async_with() {
assert_dis_snapshot!(compile_exec(
Expand Down
27 changes: 27 additions & 0 deletions crates/codegen/src/ir.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -693,6 +693,33 @@ impl CodeInfo {
None
}
}
(Instruction::LoadConst { consti }, Instruction::ToBool) => {
let consti = consti.get(curr.arg);
let constant = &self.metadata.consts[consti as usize];
if let ConstantData::Boolean { .. } = constant {
Some((curr_instr, OpArg::from(consti)))
} else {
None
}
}
(Instruction::LoadConst { consti }, Instruction::UnaryNot) => {
let constant = &self.metadata.consts[consti.get(curr.arg) as usize];
match constant {
ConstantData::Boolean { value } => {
let (const_idx, _) = self
.metadata
.consts
.insert_full(ConstantData::Boolean { value: !value });
Some((
(Instruction::LoadConst {
consti: Arg::marker(),
}),
OpArg::new(const_idx as u32),
))
}
_ => None,
}
}
Comment on lines +705 to +722
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@coderabbitai coderabbitai Bot Mar 5, 2026

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⚠️ Potential issue | 🟡 Minor

Const-fold inserts can leave dead co_consts entries.

This branch adds a new boolean constant but can orphan the original one. Since remove_unused_consts() runs before peephole, unused constants introduced here are not pruned.

💡 Suggested fix 
diff --git a/crates/codegen/src/ir.rs b/crates/codegen/src/ir.rs
@@
         if opts.optimize > 0 {
             self.dce();
             self.peephole_optimize();
+            self.remove_unused_consts();
         }
🤖 Prompt for AI Agents 
Verify each finding against the current code and only fix it if needed.

In `@crates/codegen/src/ir.rs` around lines 705 - 722, The peephole for
(Instruction::LoadConst { consti }, Instruction::UnaryNot) unconditionally
inserts a new Boolean constant with the negated value which can orphan the
original co_consts entry; instead, before calling
self.metadata.consts.insert_full, search the constant pool for an existing
ConstantData::Boolean { value: !value } and reuse its index (const_idx) if
found, and only call insert_full when no matching constant exists; update the
returned tuple to use that const_idx so you never create a duplicate orphan
constant (referencing Instruction::LoadConst, Instruction::UnaryNot,
ConstantData::Boolean, self.metadata.consts.insert_full and
remove_unused_consts()/peephole to locate the logic).

_ => None,
}
};
Expand Down
9 changes: 9 additions & 0 deletions crates/codegen/src/snapshots/rustpython_codegen__compile__tests__const_bool_not_op.snap
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