What will be this CMOS logic circuit's Truth Table?
The two leftmost transistors forms a simple not gate, but it is powered only when \$V_{x1}\$ is high. Luckily enough the passgate on the right is turned on when \$V_{x1}\$ is low instead, and directly connects the \$V_{x2}\$ input to the output.

To sum it up:


if \$V_{x1}\$ is high the output is NOT \$V_{x2}\$
if \$V_{x1}\$ is low the output is \$V_{x2}\$


in a table:

x1  x2  out
0   0   0
0   1   1
1   0   1
1   1   0


that's a xor gate.