Out of all the compiler bugs I have failed reports against over the years, only one was fixed. And the fix was applied only in the "trunk" branch, not any of the other ones still "maintained".
I learned that Gcc has a policy not to fix performance regressions on any but the development branch.
Back in the late '80s we spent fully half of each working day tracking down the trigger and workaround for cfront crashes. Kids today have it easy.
I wish this was true. It would have made my job of writing compilers so much easier.