I understand that when you compile GCC it compiles the source with:
- your system's GCC
- the compiled compiler of step 1
- the compiled compiler of step 1 again
as mentioned in https://gcc.gnu.org/onlinedocs/gccint/Makefile.html:
This means that GCC is built three times—once with the native compiler, once with the native-built compiler it just built, and once with the compiler it built the second time.
and then compares compilation results for stages 2 and 3, for which the compiler should be almost the same, except for things like:
__TIME__and__DATE__that could be present during the build- non deterministic might make those tests harder: http://stackoverflow.com/questions/14653874/deterministic-binary-output-with-g
What is the purpose of comparing stages 2 and 3? How could those 2 stages possibly differ in a meaningful way? Of course, the system could break because of things like __TIME__, but isn't that too unlikely? Are ther eothe
The fact that the GCC output is