tree 4d367433d67af533d96fcbc80abe192010219427
parent 4f364fd951eac36adbc1c8719f3e7c42974dfad1
author Ethan Nicholas <ethannicholas@google.com> 1484850720 -0500
committer Skia Commit-Bot <skia-commit-bot@chromium.org> 1484856700 +0000

Added constant propagation and better variable liveness tracking to skslc.

This allows skslc to track the values of variables with constant
values across multiple statements and replace variable references with
constant values where appropriate.

The improved liveness tracking allows skslc to realize that a
variable is no longer alive if all references to it have been
replaced. It is not yet doing much with this information; better
dead code elimination is coming in a followup change.

BUG=skia:

Change-Id: I068c5d2e9a362e75299b1de1f4575339f5ddc3bb
Reviewed-on: https://skia-review.googlesource.com/7302
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>