Impact
The order of evaluation of the arguments of the builtin functions uint256_addmod, uint256_mulmod, ecadd and ecmul does not follow source order.
• For uint256_addmod(a,b,c) and uint256_mulmod(a,b,c), the order is c,a,b.
• For ecadd(a,b) and ecmul(a,b), the order is b,a.
Note that this behaviour is problematic when the evaluation of one of the arguments produces side effects that other arguments depend on.
Patches
#3583
Workarounds
When using builtins from the list above, make sure that the arguments of the expression do not produce side effects or, if one does, that no other argument is dependent on those side effects.
References
Are there any links users can visit to find out more?
Impact
The order of evaluation of the arguments of the builtin functions
uint256_addmod,uint256_mulmod,ecaddandecmuldoes not follow source order.• For
uint256_addmod(a,b,c)anduint256_mulmod(a,b,c), the order isc,a,b.• For
ecadd(a,b)andecmul(a,b), the order isb,a.Note that this behaviour is problematic when the evaluation of one of the arguments produces side effects that other arguments depend on.
Patches
#3583
Workarounds
When using builtins from the list above, make sure that the arguments of the expression do not produce side effects or, if one does, that no other argument is dependent on those side effects.
References
Are there any links users can visit to find out more?