20. Flags

Gazprea programs are compiled with a fixed set of compiler flags for testing.

20.1. The -O2 Flag

-O2 is a mandatory compiler flag provided solely for performance testing. Code compiled with -O2 produces exactly the same observable behavior as the same code compiled without it.

When -O2 is passed, the student compiler must emit code optimized through LLVM’s -O2 optimization pipeline. Every optimization under this flag happens at the LLVM level:

• Students are not required to implement any optimizations of their own. Each optimization performed under -O2 is carried out by LLVM; the student compiler’s only responsibility is to route the flag into that pipeline.

• The project scaffolding already provides this wiring. Accepting -O2 and forwarding it to LLVM should therefore require no substantive changes to a student’s compiler.

20.2. Testing Policy

Every test is compiled with -O2. Because -O2 leaves the meaning of a program unchanged, this never alters a test’s expected output; it simply guarantees that the LLVM optimization pipeline is always exercised.