add SkNx::abs(), for now only implemented for Sk4f

src/opts/SkNx_sse.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 SkNx_sse_DEFINED
 #define SkNx_sse_DEFINED
 
@@ skipping 158 matching lines @@
     SkNx operator == (const SkNx& o) const { return _mm_cmpeq_ps (fVec, o.fVec); }
     SkNx operator != (const SkNx& o) const { return _mm_cmpneq_ps(fVec, o.fVec); }
     SkNx operator  < (const SkNx& o) const { return _mm_cmplt_ps (fVec, o.fVec); }
     SkNx operator  > (const SkNx& o) const { return _mm_cmpgt_ps (fVec, o.fVec); }
     SkNx operator <= (const SkNx& o) const { return _mm_cmple_ps (fVec, o.fVec); }
     SkNx operator >= (const SkNx& o) const { return _mm_cmpge_ps (fVec, o.fVec); }
 
     static SkNx Min(const SkNx& l, const SkNx& r) { return _mm_min_ps(l.fVec, r.fVec); }
     static SkNx Max(const SkNx& l, const SkNx& r) { return _mm_max_ps(l.fVec, r.fVec); }
 
+    SkNx abs() const { return _mm_andnot_ps(_mm_set1_ps(-0.0f), fVec); }
+
     SkNx  sqrt() const { return _mm_sqrt_ps (fVec);  }
     SkNx rsqrt0() const { return _mm_rsqrt_ps(fVec); }
     SkNx rsqrt1() const { return this->rsqrt0(); }
     SkNx rsqrt2() const { return this->rsqrt1(); }
 
     SkNx       invert() const { return SkNx(1) / *this; }
     SkNx approxInvert() const { return _mm_rcp_ps(fVec); }
 
     template <int k> float kth() const {
         SkASSERT(0 <= k && k < 4);
@@ skipping 185 matching lines @@
                      _mm_packus_epi16(_mm_packus_epi16(_mm_cvttps_epi32(a.fVec),
                                                        _mm_cvttps_epi32(b.fVec)),
                                       _mm_packus_epi16(_mm_cvttps_epi32(c.fVec),
                                                        _mm_cvttps_epi32(d.fVec))));
 }
 
 
 }  // namespace
 
 #endif//SkNx_sse_DEFINED