tree 619932bff6df0fb7e74162a13d9004f02cc2ed4a
parent 77ea58e784e8abbdca17cf8afe29cdc0a109ad42
author John Stiles <johnstiles@google.com> 1614092284 -0500
committer John Stiles <johnstiles@google.com> 1614094704 +0000

Fix switch optimization pass.

The optimizer now properly recognizes all types of exits from a switch
statement. Break, continue and return are all potential exits and need
to be considered when determining the exit path from the switch.

Previously, dead code elimination was hiding the effects of this bug
from us, but it meant that an optimized switch had the potential to
generate lots of worthless IR nodes which then needed to be detected and
eliminated by the CFG. In particular, this affected the enum form of
blend, causing a catastrophic amount of extra work to be done.

Change-Id: If857e38cadfc016884624ea4db25a273ad3dce5b
Bug: skia:11352
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/372958
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>