Absolutely - this is exactly what I said ages ago in this thread (which is just going round in circles). Language compliance testing is just that, language compliance testing. The compiler can pass standards compliance testing and still have bugs in its code generation (the example I gave of an interrupt stack frame) so the fact it passes language compliance testing does not lessen the need to test your code. After all, the engineers might have a different idea to what the standard says as the compliance test writers.
If you app is really that safety critical then your test coverage criteria should be strict enough that your testing finds the bugs making the compiler choice incidental. Testing requirements to object code, that is, requirements to the actual output of the compiler, means your tests can show your code is correctly fulfilling its requirements whether the compiler is compliant to the standard or not - it (almost) doesn't matter - its whether your implementation matches the requirements that matters (the requirements are probably wrong though ;o)
I'm not saying there is no value in language compliance testing, but it is not a magic bullet that makes much difference to anything else you do in the development other than show the required due diligence, use of state of the art, etc.