Test.

test/libsolidity/semanticTests/viaYul/erc20.sol

@@ -0,0 +1,104 @@
+pragma solidity ^0.5.0;
+
+contract ERC20 {
+    event Transfer(address indexed from, address indexed to, uint256 value);
+    event Approval(address indexed owner, address indexed spender, uint256 value);
+
+    mapping (address => uint256) private _balances;
+    mapping (address => mapping (address => uint256)) private _allowances;
+    uint256 private _totalSupply;
+
+    constructor() public {
+        _mint(msg.sender, 20);
+    }
+
+    function totalSupply() public view returns (uint256) {
+        return _totalSupply;
+    }
+
+    function balanceOf(address owner) public view returns (uint256) {
+        return _balances[owner];
+    }
+
+    function allowance(address owner, address spender) public view returns (uint256) {
+        return _allowances[owner][spender];
+    }
+
+    function transfer(address to, uint256 value) public returns (bool) {
+        _transfer(msg.sender, to, value);
+        return true;
+    }
+
+    function approve(address spender, uint256 value) public returns (bool) {
+        _approve(msg.sender, spender, value);
+        return true;
+    }
+
+    function transferFrom(address from, address to, uint256 value) public returns (bool) {
+        _transfer(from, to, value);
+        // The subtraction here will revert on overflow.
+        _approve(from, msg.sender, _allowances[from][msg.sender] - value);
+        return true;
+    }
+
+    function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
+        // The addition here will revert on overflow.
+        _approve(msg.sender, spender, _allowances[msg.sender][spender] + addedValue);
+        return true;
+    }
+
+    function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
+        // The subtraction here will revert on overflow.
+        _approve(msg.sender, spender, _allowances[msg.sender][spender] - subtractedValue);
+        return true;
+    }
+
+    function _transfer(address from, address to, uint256 value) internal {
+        require(to != address(0), "ERC20: transfer to the zero address");
+
+        // The subtraction and addition here will revert on overflow.
+        _balances[from] = _balances[from] - value;
+        _balances[to] = _balances[to] + value;
+        emit Transfer(from, to, value);
+    }
+
+    function _mint(address account, uint256 value) internal {
+        require(account != address(0), "ERC20: mint to the zero address");
+
+        // The additions here will revert on overflow.
+        _totalSupply = _totalSupply + value;
+        _balances[account] = _balances[account] + value;
+        emit Transfer(address(0), account, value);
+    }
+
+    function _burn(address account, uint256 value) internal {
+        require(account != address(0), "ERC20: burn from the zero address");
+
+        // The subtractions here will revert on overflow.
+        _totalSupply = _totalSupply - value;
+        _balances[account] = _balances[account] - value;
+        emit Transfer(account, address(0), value);
+    }
+
+    function _approve(address owner, address spender, uint256 value) internal {
+        require(owner != address(0), "ERC20: approve from the zero address");
+        require(spender != address(0), "ERC20: approve to the zero address");
+
+        _allowances[owner][spender] = value;
+        emit Approval(owner, spender, value);
+    }
+
+    function _burnFrom(address account, uint256 value) internal {
+        _burn(account, value);
+        _approve(account, msg.sender, _allowances[account][msg.sender] - value);
+    }
+}
+// ====
+// compileViaYul: true
+// ----
+// totalSupply() -> 20
+// transfer(address,uint256): 2, 5 -> true
+// decreaseAllowance(address,uint256): 2, 0 -> true
+// decreaseAllowance(address,uint256): 2, 1 -> FAILURE
+// transfer(address,uint256): 2, 14 -> true
+// transfer(address,uint256): 2, 2 -> FAILURE