tree 6c71d4b1a170aa7291df4c1392d5395a41d63437
parent 87cab44823dbf25860e86e3e5d3377fb9246c592
author Benoit Jacob <benoitjacob@google.com> 1578338869 -0800
committer TensorFlower Gardener <gardener@tensorflow.org> 1578339713 -0800

Keep only the simple auxv method for detecting dotprod instructions.
It's available on Linux >= 4.15 in general; on Android, at least Linux 4.14.111 thanks to a late backport. This was backported just before the Android 10 release, so this is leaving out pre-release Android 10 builds as well as earlier Android versions.

Part of the rationale for submitting this now is an understanding that most devices with new hardware supporting dotprod instructions either shipped with Android 10 in the first place (Pixel4) or have received an Android 10 update already (LG G8, Samsung Galaxy S10, Note 10). We are probably leaving some devices unsupported, but conversely the signal-handler detection method that this is removing was reported to cause crashes on other devices, so this is a compromise. At least now we won't crash anywhere, at worst some devices won't get the speedup from dotprod instructions.

PiperOrigin-RevId: 288340160
Change-Id: I9f1b934f4e3996456af0489b780d567596f6db92