shl causes undefined behaviour

[arnetheduck]

var x = 10000
echo x shl 1000

       T1_[0] = dollar___systemZdollars_3((NI)((NU64)(x__testit_1) << (NU64)(((NI) 1000))));

Shifting by more than sizeof(x) * 8 is undefined behaviour in C - moreover, the conversions between int and uint here are quite wonky.
Nim can either flag the behaviour or do min(sizeof(x) * 8, shift) which is probably what is intended for large shifts

nim 1.6.6

[arnetheduck]

ditto shifting by negative numbers

[RSDuck]

Nim can either flag the behaviour or do min(sizeof(x) * 8, shift) which is probably what is intended for large shifts

it probably makes more sense to mask shifts (shift and (sizeof(x)*8-1)) as pretty much all processor architectures do this (except for 32-bit ARM) and C compilers will just optimise the and away.

[metagn]

See also #11555