[tom_mellior]

> Sometimes the compiler needs to generate a random value and base part of the compilation on that value.

As a compiler engineer with experience (among others) in LLVM and GCC this is the first time I'm hearing of this. Could you provide more details or a source?

I can't imagine where such behavior would be useful, let alone required. The only slightly plausible scenario I can think of would be representing some internal data structures as hash tables with random seeds to avoid denial-of-service attacks. But then the compiled code would still have to rely on, at some point, picking an arbitrary element out of such a hash table. I can't think of contexts inside a compiler where this would be a useful thing to do.

[Luker88]

No experience here, but from the manpage:

-frandom-seed=string

  This option provides a seed that GCC uses in place of random numbers in generating certain symbol names that have to be different in every compiled file.  It is also used to place unique stamps in coverage data files and the object files that produce them.  You can use the -frandom-seed option to produce reproducibly identical object files.

though my example/guess on branch prediction is probably wrong

[tom_mellior]

Ah, thanks. Looks like this only applies to symbol names, so the generated executable code should be deterministic, only symbol table entries might differ.