You could use nm to determine which references to memset and memcpy have been replaced by the __intel_fast_ versions from the icc library. There should be no built-in version with icc, unless you mean those __intel_fast_ versions. As the other response indicated, current glibc versions should be good for most purposes as well. I can't see what your choice of malloc would imply; maybe you mean which functions does your non-standard malloc use. Again, nm should be a useful tool.
Apparently, you're not asking about AVX optimizations; those don't have great importance on the Sandy Bridge implementation, since the hardware splits 256-bit moves into 128-bit pieces. The main issue for big aligned memset/memmove strings is the cutover point to nontemporal, which would be application dependent.