Crashes are the easier bugs to report, but often the most important compiler bugs are silent miscompilations that go unnoticed. With C compilers in particular, it's not easy to non-conclusively demonstrate a bug/convince the developers that the compiler is actually buggy (a lot of C standard lawyering is at play when it comes to subtle undefined behaviors).
[disclosure: I have been involved with the initial phase of "EMI" compiler validation work that's linked] One of the great strengths of EMI has been its ability to identify a lot of miscompliations in particular. In fact, while we did not fix the bugs ourselves, I would say the majority of the time spent was probably in reducing the bugs in a short program that manifested the issues and engaging with the developers to prove the bug is not an undefined behavior. I remember from my days that the majority of bugs we reported were miscompilations, not crashes, which took a lot of time to report. Even with simple crashes, you probably need to reduce the bug as the developers don't usually appreciate attaching a 7MB source file to your bug report!
[disclosure: I have been involved with the initial phase of "EMI" compiler validation work that's linked] One of the great strengths of EMI has been its ability to identify a lot of miscompliations in particular. In fact, while we did not fix the bugs ourselves, I would say the majority of the time spent was probably in reducing the bugs in a short program that manifested the issues and engaging with the developers to prove the bug is not an undefined behavior. I remember from my days that the majority of bugs we reported were miscompilations, not crashes, which took a lot of time to report. Even with simple crashes, you probably need to reduce the bug as the developers don't usually appreciate attaching a 7MB source file to your bug report!