Malloc -Z

[grarpamp]

Was reading malloc(3) while chasing corruption suspects.
Does the presence of -Z imply that without it, programs
can be allocated dirty (non-zeroed) memory?
If so, it seems running with -Z would be prudent if one cares.
Therefore, what is the rough percent performance
impact of -Z compared to default malloc?

Bonus:
What would be needed to make the useful streams:
/dev/one
/dev/10
/dev/01
In addition to /dev/zero.