Roll skia/third_party/skcms 28e8b32..14c31bf (6 commits)

https://skia.googlesource.com/skcms.git/+log/28e8b32..14c31bf

2018-05-15 mtklein@chromium.org temporarily turn on SKCMS_LEGACY_POWF for GN builds
2018-05-15 mtklein@chromium.org spin sources list out of BUILD.gn
2018-05-14 mtklein@chromium.org Reland "remove loop in powf"
2018-05-14 mtklein@chromium.org Revert "remove loop in powf"
2018-05-14 brianosman@google.com Adjust fuzzers to test against parametric approximated tables
2018-05-14 mtklein@chromium.org remove loop in powf


The AutoRoll server is located here: https://skcms-skia-roll.skia.org

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.



CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
TBR=herb@google.com

Change-Id: I0ff3903370a7c07ce7e194ab44c35ff546b7f973
Reviewed-on: https://skia-review.googlesource.com/128284
Commit-Queue: skcms-skia-autoroll <skcms-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Reviewed-by: skcms-skia-autoroll <skcms-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>

1 files changed, 7 insertions, 5 deletions

diff --git a/third_party/skcms/src/Transform_inl.h b/third_party/skcms/src/Transform_inl.h
index debdf68a88..15f19a0638 100644
--- a/third_party/skcms/src/Transform_inl.h
+++ b/third_party/skcms/src/Transform_inl.h
@@ -221,16 +221,18 @@ SI ATTR F NS(approx_exp2_)(F x) {
 #define approx_exp2 NS(approx_exp2_)
 
 SI ATTR F NS(approx_pow_)(F x, float y) {
-    // Handling all the integral powers first increases our precision a little.
+#if defined(SKCMS_LEGACY_POWF)
     F r = F1;
     while (y >= 1.0f) {
         r *= x;
         y -= 1.0f;
     }
-
-    // TODO: The rest of this could perhaps be specialized further knowing 0 <= y < 1.
-    assert (0 <= y && y < 1);
-    return (F)if_then_else((x == F0) | (x == F1), x, r * approx_exp2(approx_log2(x) * y));
+    return (F)if_then_else((x == F0) | (x == F1), x
+                                                , r * approx_exp2(approx_log2(x) * y));
+#else
+    return (F)if_then_else((x == F0) | (x == F1), x
+                                                , approx_exp2(approx_log2(x) * y));
+#endif
 }
 #define approx_pow NS(approx_pow_)