In 32-bit -mia32 there is no SIMD, so there's no way to turn it on (or off).
In SSE compilation with icpc, -no-vec (-no-simd with current compilers) would turn off generation of SIMD in the generated code, as would setting -O1. If you want to stop the use of fast_memcpy and fast_memset and such library functions, there may be another option for that.