[PATCH] D21560: Relax the clearance calculating for breaking partial register dependency.

[Michael Kuperstein via llvm-commits]

mkuper added a comment.

> Is there already a regression test to show that we're not adding instructions if we're in MinSize mode?


I believe we currently add the xors in MinSize mode, and, as I wrote on PR22024, I think it's justified.
I guess it's a question of how -Oz is defined - whether it's "make code smaller at all costs", or (as the manual currently says):

- -Os: Like -O2 with extra optimizations to reduce code size.
- -Oz: Like -Os (and thus -O2), but reduces code size further.

My gut feeling is that omitting the xor is not a good performance/size trade-off even for -Oz.


http://reviews.llvm.org/D21560