> This case is covered by Wilco's previous reply: > > https://gcc.gnu.org/ml/gcc-patches/2017-08/msg00575.html
Which I don't understand: > No it's perfectly safe - it becomes an integer-only shift after the > split since it keeps the masking as part of the pattern. Let say we have your first example: long f1(long x, int i) { return x >> (64 - i); } If "i" is -2, this should be a shift of 66 (which is indeed, technically undefined), but becomes a shift of 62. What am I missing?