Strict fp-to-int and int-to-fp conversions can be handled in the same way that the non-strict versions are (by using the appropriate instruction or converting to a function call when we have no instruction).
I think you may need add option "-disable-strictnode-mutation" to ensure the code generation doesn't come from mutation before strict FP default enabled. The same to other patches.
Currently a lot of it is coming from strict node mutation. The tests here are primarily for making sure opt doesn't crash with an assertion if you're using it with the default options.