add new target-specific abi0 pass

The general idea is to give abis a
chance to talk before we've done all
the optimizations. Currently, all
targets eliminate {par,arg,ret}{sb,ub,...}
during this pass. The forthcoming
arm64_apple will, however, insert
proper extensions during abi0.

Moving forward abis can, for example,
lower small-aggregates passing there
so that memory optimizations can
interact better with function calls.

0 files changed, 0 insertions, 0 deletions