Match select IR node with isel-pseudo SelNoCond which expands to:

SelNoCond res, a, x, y
 ==>
bneq a, ZERO, BB1
br BB2
BB1:
resx = COPY x
br ExitBB
BB2:
resy = COPY y
br ExitBB
ExitBB:
res = PHI resx, resy