Free functions.

test/libsolidity/semanticTests/freeFunctions/recursion.sol

@@ -0,0 +1,23 @@
+function exp(uint base, uint exponent) pure returns (uint power) {
+    if (exponent == 0)
+        return 1;
+    power = exp(base, exponent / 2);
+    power *= power;
+    if (exponent & 1 == 1)
+        power *= base;
+}
+
+contract C {
+  function g(uint base, uint exponent) public pure returns (uint) {
+      return exp(base, exponent);
+  }
+}
+// ====
+// compileViaYul: also
+// ----
+// g(uint256,uint256): 0, 0 -> 1
+// g(uint256,uint256): 0, 1 -> 0x00
+// g(uint256,uint256): 1, 0 -> 1
+// g(uint256,uint256): 2, 3 -> 8
+// g(uint256,uint256): 3, 10 -> 59049
+// g(uint256,uint256): 2, 255 -> -57896044618658097711785492504343953926634992332820282019728792003956564819968