To do this with a clean conscience, I needed to convert the unroll-
counting logic from a linear time algorithm to constant-time. Getting
all the edge cases correct requires a lot of care, and there are now
plenty of unit tests.
Change-Id: I620909d069ac425b7310e345bf80ec844fe035f8
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/445643
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
An ES2-compatible for loop supports six separate rel-ops:
< <= > >= != ==
Each rel-op, in addition to its expected usage, is also able to
represent a loop which never terminates, as well as a loop which
terminates instantly. Since SkVM unrolls these loops, we should make
sure we do it properly. We now have unit tests for all of these cases.
Change-Id: Icae04d48bc158bf8c0c98db97f76756a1a29110c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/445756
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
Change-Id: Id894eb70273454716eb33c85dff2056333e90cdd
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/445281
Reviewed-by: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Expressions like `x * 1`, `x *= 1`, `x + 0`, `x * 0`, or `0 / x` don't
actually do anything, and can be simplified to just `x` or `0`. (The
zero case must also check that `x` doesn't have side effects, because
`0 * myFunction()` still needs to call `myFunction`.)
`0 - x` is also detected and rewritten as `-x`.
`0 / 0` is left as-is.
This logic works for scalars and vectors; matrices are left as-is.
A similar optimization also occurs in the constant-propagation pass, so
we see almost no diffs in the tests. If control-flow analysis is turned
off, we do see some improvements. (I didn't reuse the existing code at
all, since it was designed around rewriting the CFG tree, but the
concept was identical.)
Change-Id: Ia99cd81f1d4cd3dafaa43ccac6a2261e3257a185
Bug: skia:11343
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/380356
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
This will allow us to load these inputs for unit testing in `dm`.
Change-Id: Id256ba7c30d3ec94b98048e47af44cf9efe580d5
Bug: skia:11009
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/357282
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
