Stack Alignment for Numerics

[dsimcha]

Does the freezing of the D2 language spec and the publication of TDPL preclude
fixing low level ABI issues like stack alignment?  I have some numerics code
that is taking a massive performance hit because the stack keeps ending up
aligned such that none of my doubles are aligned on 8-byte boundaries,
resulting in something like a 2x performance hit.

If not, this is a pretty serious performance problem.  Is there a "standard"
solution to the stack alignment problem that will allow consistently good
performance on numerics code that uses double-precision floats?