"-ftrapv" and "-fwrapv": Which is better for efficiency?

Question

From GNU's website:

• -ftrapv

  This option generates traps for signed overflow on addition, subtraction, multiplication operations.

• -fwrapv

This option instructs the compiler to assume that signed arithmetic overflow of addition, subtraction and multiplication wraps around using twos-complement representation. This flag enables some optimizations and disables others.

https://gcc.gnu.org/onlinedocs/gcc-4.4.2/gcc/Code-Gen-Options.html

I have two questions:

1. Which of these options is better for performance?
2. What what does it mean when the -ftrapv definition says it generates "traps?" Does this mean exceptions? (I'm guessing no, but it's worth asking.)