radiance · commit

lang: Infer literal-first comparison types

3c89648cb44d17a6578824059423541759f9208c900c19fcfe00cb4161ff5f06

Ordering comparisons always selected the left operand’s type
during lowering. An unsuffixed left literal therefore forced
signed comparison semantics even when the concrete right operand
was unsigned.

Validate ordering operand compatibility and select the non-literal
operand type in both expression and fused-branch lowering.

Assisted-by: Codex:gpt-5.6-sol

Alexis Sellier committed 1 month ago 1 parent b2271358

lib/std/lang/lower.rad +9 -3

    // Try fused compare-and-branch for simple scalar comparisons.
    if let case ast::NodeValue::BinOp(binop) = cond.value {
        let leftTy = try typeOf(self, binop.left);
        let rightTy = try typeOf(self, binop.right);
        if not isAggregateType(leftTy) and not isAggregateType(rightTy) {
            let unsigned = isUnsignedType(leftTy);
            let operandTy = scalarComparisonType(leftTy, rightTy);
            let unsigned = isUnsignedType(operandTy);
            if let op = cmpOpFrom(binop.op, unsigned) {
                let a = try lowerExpr(self, binop.left);
                let b = try lowerExpr(self, binop.right);
                let typ = ilType(self.low, leftTy);
                let typ = ilType(self.low, operandTy);

                // Swap operands if needed.
                match binop.op {
                    case ast::BinaryOp::Gt => // `a > b` = `b < a`
                        try emitBrCmp(self, op, typ, b, a, thenBlock, elseBlock),


        return il::Val::Reg(resultReg);
    }
}

/// Select the concrete operand type for a scalar comparison.
fn scalarComparisonType(left: resolver::Type, right: resolver::Type) -> resolver::Type {
    return right if left == resolver::Type::Int else left;
}

/// Convert a binary operator to a comparison op, if applicable.
/// For `Gt`, caller must swap operands: `a > b = b < a`.
/// For `Gte`/`Lte`, caller must swap branch labels: `a >= b = !(a < b)`.
/// For `Lte`, caller must also swap operands: `a <= b = !(b < a)`.
fn cmpOpFrom(op: ast::BinaryOp, unsigned: bool) -> ?il::CmpOp {

        }
        if isAggregateType(rightTy) {
            let lhs = try wrapInOptional(self, a, rightTy);
            return try emitAggregateEqOp(self, binop.op, rightTy, lhs, b);
        }
        set resultTy = leftTy;
        set resultTy = scalarComparisonType(leftTy, rightTy);
    }
    return emitScalarBinOp(self, binop.op, ilType(self.low, resultTy), a, b, isUnsignedType(resultTy));
}

/// Emit an aggregate equality or inequality comparison.

lib/std/lang/resolver.rad +8 -1

                }
            }
            let leftTy = try checkNumeric(self, binop.left);
            let rightTy = try checkNumeric(self, binop.right);

            // Ordering comparisons return `bool`, not the operand type.
            // Ordering comparisons use the concrete operand type. Only an
            // unsuffixed integer expression may differ from that type.
            match binop.op {
                case ast::BinaryOp::Lt, ast::BinaryOp::Gt,
                     ast::BinaryOp::Lte, ast::BinaryOp::Gte => {
                    if leftTy <> rightTy and leftTy <> Type::Int and rightTy <> Type::Int {
                        throw emitTypeMismatch(self, binop.right, TypeMismatch {
                            expected: leftTy,
                            actual: rightTy,
                        });
                    }
                    set resultTy = Type::Bool;
                } else => {
                    if leftTy == rightTy {
                        set resultTy = leftTy;
                    } else if leftTy == Type::Int {

test/tests/compare.literal.first.u64.rad added +16 -0

1	+	//! returns: 0
2	+	//! Literal-first ordering must use the concrete operand's unsigned type.
3	+
4	+	fn isPositive(value: u64) -> bool {
5	+	if 0 < value {
6	+	return true;
7	+	}
8	+	return false;
9	+	}
10	+
11	+	@default fn main() -> i32 {
12	+	if isPositive(0xffffffffffffffff) {
13	+	return 0;
14	+	}
15	+	return 1;
16	+	}

2255	2255		// Try fused compare-and-branch for simple scalar comparisons.
2256	2256		if let case ast::NodeValue::BinOp(binop) = cond.value {
2257	2257		let leftTy = try typeOf(self, binop.left);
2258	2258		let rightTy = try typeOf(self, binop.right);
2259	2259		if not isAggregateType(leftTy) and not isAggregateType(rightTy) {
2260		-	let unsigned = isUnsignedType(leftTy);
	2260	+	let operandTy = scalarComparisonType(leftTy, rightTy);
	2261	+	let unsigned = isUnsignedType(operandTy);
2261	2262		if let op = cmpOpFrom(binop.op, unsigned) {
2262	2263		let a = try lowerExpr(self, binop.left);
2263	2264		let b = try lowerExpr(self, binop.right);
2264		-	let typ = ilType(self.low, leftTy);
	2265	+	let typ = ilType(self.low, operandTy);
2265	2266
2266	2267		// Swap operands if needed.
2267	2268		match binop.op {
2268	2269		case ast::BinaryOp::Gt => // `a > b` = `b < a`
2269	2270		try emitBrCmp(self, op, typ, b, a, thenBlock, elseBlock),

5883	5884
5884	5885		return il::Val::Reg(resultReg);
5885	5886		}
5886	5887		}
5887	5888
	5889	+	/// Select the concrete operand type for a scalar comparison.
	5890	+	fn scalarComparisonType(left: resolver::Type, right: resolver::Type) -> resolver::Type {
	5891	+	return right if left == resolver::Type::Int else left;
	5892	+	}
	5893	+
5888	5894		/// Convert a binary operator to a comparison op, if applicable.
5889	5895		/// For `Gt`, caller must swap operands: `a > b = b < a`.
5890	5896		/// For `Gte`/`Lte`, caller must swap branch labels: `a >= b = !(a < b)`.
5891	5897		/// For `Lte`, caller must also swap operands: `a <= b = !(b < a)`.
5892	5898		fn cmpOpFrom(op: ast::BinaryOp, unsigned: bool) -> ?il::CmpOp {

5952	5958		}
5953	5959		if isAggregateType(rightTy) {
5954	5960		let lhs = try wrapInOptional(self, a, rightTy);
5955	5961		return try emitAggregateEqOp(self, binop.op, rightTy, lhs, b);
5956	5962		}
5957		-	set resultTy = leftTy;
	5963	+	set resultTy = scalarComparisonType(leftTy, rightTy);
5958	5964		}
5959	5965		return emitScalarBinOp(self, binop.op, ilType(self.low, resultTy), a, b, isUnsignedType(resultTy));
5960	5966		}
5961	5967
5962	5968		/// Emit an aggregate equality or inequality comparison.

6505	6505		}
6506	6506		}
6507	6507		let leftTy = try checkNumeric(self, binop.left);
6508	6508		let rightTy = try checkNumeric(self, binop.right);
6509	6509
6510		-	// Ordering comparisons return `bool`, not the operand type.
	6510	+	// Ordering comparisons use the concrete operand type. Only an
	6511	+	// unsuffixed integer expression may differ from that type.
6511	6512		match binop.op {
6512	6513		case ast::BinaryOp::Lt, ast::BinaryOp::Gt,
6513	6514		ast::BinaryOp::Lte, ast::BinaryOp::Gte => {
	6515	+	if leftTy <> rightTy and leftTy <> Type::Int and rightTy <> Type::Int {
	6516	+	throw emitTypeMismatch(self, binop.right, TypeMismatch {
	6517	+	expected: leftTy,
	6518	+	actual: rightTy,
	6519	+	});
	6520	+	}
6514	6521		set resultTy = Type::Bool;
6515	6522		} else => {
6516	6523		if leftTy == rightTy {
6517	6524		set resultTy = leftTy;
6518	6525		} else if leftTy == Type::Int {