de-proc sk_float_rsqrt

src/opts/SkFloatingPoint_opts.h

-/*
- * Copyright 2015 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef SkFloatingPoint_opts_DEFINED
-#define SkFloatingPoint_opts_DEFINED
-
-#include "SkFloatingPoint.h"
-
-namespace SK_OPTS_NS {
-
-#if defined(SK_ARM_HAS_NEON)
-    static float rsqrt(float x) {
-        return sk_float_rsqrt(x);  // This sk_float_rsqrt copy will take the NEON compile-time path.
-    }
-#else
-    static float rsqrt(float x) {

[mtklein, 2016/01/22 13:53:02]

The portable rsqrt() logic has not changed.

It's still covered by the unit test in MathTest, but you're right, no Test bot
of ours will run it now (some do continue to compile it).

-        // Get initial estimate.
-        int i = *SkTCast<int*>(&x);
-        i = 0x5F1FFFF9 - (i>>1);
-        float estimate = *SkTCast<float*>(&i);
-
-        // One step of Newton's method to refine.
-        const float estimate_sq = estimate*estimate;
-        estimate *= 0.703952253f*(2.38924456f-x*estimate_sq);
-        return estimate;
-    }
-#endif
-
-}  // namespace SK_OPTS_NS
-
-#endif//SkFloatingPoint_opts_DEFINED