solidity/test/formal/checked_int_div.py

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from rule import Rule
from opcodes import *
from util import *
"""
Overflow checked signed integer division.
"""
n_bits = 256
type_bits = 8
while type_bits <= n_bits:
rule = Rule()
# Input vars
X_short = BitVec('X', type_bits)
Y_short = BitVec('Y', type_bits)
# Z3's overflow conditions
actual_overflow = Not(BVSDivNoOverflow(X_short, Y_short))
# cast to full n_bits values
X = BVSignedUpCast(X_short, n_bits)
Y = BVSignedUpCast(Y_short, n_bits)
# Constants
minValue = BVSignedMin(type_bits, n_bits)
# Overflow check in YulUtilFunction::overflowCheckedIntDivFunction
overflow_check = AND(EQ(X, minValue), EQ(Y, SUB(0, 1)))
rule.check(actual_overflow, overflow_check != 0)
type_bits *= 2