I'm a big fan of aarch64's csel family of instructions. A single instruction can evaluate rd = cond ? rs1 : f(rs2), where cond is any condition code and f is any of f0(x) = x or f1(x) = x+1 or f2(x) = ~x or or f3(x) = -x. Want to convert a condition to a boolean? Use f1 with rs1 == rs2 == x0. Want to convert a condition to a mask? Use f2 with rs1 == rs2 == x0. Want to compute an absolute value? Use f3 with rs1 == rs2. It is pleasing that the composition of f1 and f2 is f3. I could continue e...
