[FunC] Fix a bug with << operator to zero value (#1262)

Author: tolk-vm

crypto/func/auto-tests/tests/bit-operators.fc

@@ -0,0 +1,53 @@
+
+int lshift() {
+    return (1 << 0) == 1;
+}
+
+int rshift() {
+    return (1 >> 0) == 1;
+}
+
+int lshift_var(int i) {
+    return (1 << i) == 1;
+}
+
+int rshift_var(int i) {
+    return (1 >> i) == 1;
+}
+
+int main(int x) {
+    if (x == 0) {
+        return lshift();
+    } elseif (x == 1) {
+        return rshift();
+    } elseif (x == 2) {
+        return lshift_var(0);
+    } elseif (x == 3) {
+        return rshift_var(0);
+    } elseif (x == 4) {
+        return lshift_var(1);
+    } else {
+        return rshift_var(1);
+    }
+}
+
+int is_claimed(int index) method_id(11) {
+    int claim_bit_index = index % 256;
+    int mask = 1 << claim_bit_index;
+    return (255 & mask) == mask;
+}
+
+
+{-
+    method_id | in  | out
+TESTCASE | 0  | 0   | -1
+TESTCASE | 0  | 1   | -1
+TESTCASE | 0  | 2   | -1
+TESTCASE | 0  | 3   | -1
+TESTCASE | 0  | 4   |  0
+TESTCASE | 0  | 5   |  0
+TESTCASE | 11 | 0   | -1
+TESTCASE | 11 | 1   | -1
+TESTCASE | 11 | 256 | -1
+TESTCASE | 11 | 8   |  0
+-}

crypto/func/builtins.cpp

@@ -264,7 +264,7 @@ int emulate_lshift(int a, int b) {
   }
   int t = ((b & VarDescr::_NonZero) ? VarDescr::_Even : 0);
   t |= b & VarDescr::_Finite;
-  return emulate_mul(a, VarDescr::_Int | VarDescr::_Pos | VarDescr::_NonZero | VarDescr::_Even | t);
+  return emulate_mul(a, VarDescr::_Int | VarDescr::_Pos | VarDescr::_NonZero | t);
 }
 
 int emulate_div(int a, int b) {
@@ -310,7 +310,7 @@ int emulate_rshift(int a, int b) {
   }
   int t = ((b & VarDescr::_NonZero) ? VarDescr::_Even : 0);
   t |= b & VarDescr::_Finite;
-  return emulate_div(a, VarDescr::_Int | VarDescr::_Pos | VarDescr::_NonZero | VarDescr::_Even | t);
+  return emulate_div(a, VarDescr::_Int | VarDescr::_Pos | VarDescr::_NonZero | t);
 }
 
 int emulate_mod(int a, int b, int round_mode = -1) {

crypto/func/func.h

@@ -45,7 +45,7 @@ extern std::string generated_from;
 
 constexpr int optimize_depth = 20;
 
-const std::string func_version{"0.4.4"};
+const std::string func_version{"0.4.5"};
 
 enum Keyword {
   _Eof = -1,