YARPGen is a generative (as opposed to mutation-based) compiler fuzzer that we developed. It previously focused on testing scalar optimizations, but after a recent substantial upgrade, it now supports a collection of strategies for stress-testing loop optimizations. To achieve this, we ensure that its tests contain optimization prerequisites and interesting data access patterns (e.g., stencils), which are necessary to trigger loop optimizations (e.g., GVN). YARPGen's internal intermediate representation allows us to lower generated tests to C, C++, DPC++, and ISPC. Along with an automated testing system, this new version of YARPGen has discovered more than 120 bugs in compilers such as Clang, GCC, the ISPC compiler, and the DPC++ compiler, in addition to finding a comparable number of bugs in proprietary compilers.