Possibly, as Intel's compiler uses dynamic code-path selection based on the processor.
But more likely, it would mean slower code execution, as the code path wouldn't be optimised for AMD:
i.e. if the processor check thinks it's running an i7 Sandy Bridge, with an SSE float divide latency of 11, but the AMD chip has a latency of 23, so the unrolled loop that worked well for the i7 doesn't work at all for the AMD chip.
Except it turns out not to work that way - most of the optimisations turn out to be general ones, and some of the non-optimised code paths AMD gets for stuff like string copying are slower than a naive implementation. (Actually, Intel wound up having to fudge the CPUID result on their newer processors for this reason. Otherwise binaries compiled on their older compilers would detect an unrecognised chip and run the slow path - including some of the benchmarkers reviewers would use to compare the two!)
But more likely, it would mean slower code execution, as the code path wouldn't be optimised for AMD:
i.e. if the processor check thinks it's running an i7 Sandy Bridge, with an SSE float divide latency of 11, but the AMD chip has a latency of 23, so the unrolled loop that worked well for the i7 doesn't work at all for the AMD chip.