  We investigate QCD with adjoint Dirac fermions on $\mathbb{R}^3\times S^1$
with generic boundary conditions for fermions along $S^1$. By means of
perturbation theory, semiclassical methods and a chiral effective model, we
elucidate a rich phase structure in the space spanned by the $S^1$
compactification scale $L$, twisted fermionic boundary condition $\phi$ and the
fermion mass $m$. We found various phases with or without chiral and center
symmetry breaking, separated by first- and second-order phase transitions,
which in specific limits ($\phi=0$, $\phi=\pi$, $L\to 0$ and $m\to \infty$)
reproduce known results in the literature. In the center-symmetric phase at
small $L$, we show that Unsal's bion-induced confinement mechanism is at work
but is substantially weakened at $\phi\ne 0$ by a linear potential between
monopoles. Through an analytic and numerical study of the PNJL model, we show
that the order parameters for center and chiral symmetries (i.e., Polyakov loop
and chiral condensate) are strongly intertwined at $\phi\ne 0$. Due to this
correlation, a deconfined phase can intervene between a weak-coupling
center-symmetric phase at small $L$ and a strong-coupling one at large $L$.
Whether this happens or not depends on the ratio of the dynamical fermion mass
to the energy scale of the Yang-Mills theory. Implication of this possibility
for resurgence in gauge theories is briefly discussed. In an appendix, we study
the index of the adjoint Dirac operator on $\mathbb{R}^3\times S^1$ with
twisted boundary conditions, which is important for semiclassical analysis of
monopoles.
