solidity/test/formal/combine_byte_shr_2.py
2021-10-13 16:20:10 +02:00

29 lines
384 B
Python

from opcodes import BYTE, SHR, DIV
from rule import Rule
from z3 import BitVec, ULT
"""
byte(A, shr(B, X))
given A < B / 8
->
0
"""
rule = Rule()
n_bits = 256
# Input vars
X = BitVec('X', n_bits)
A = BitVec('A', n_bits)
B = BitVec('B', n_bits)
# Non optimized result
nonopt = BYTE(A, SHR(B, X))
# Optimized result
opt = 0
rule.require(ULT(A, DIV(B,8)))
rule.check(nonopt, opt)