Revert of skcpu: sse4.1 floor, f16c f16<->f32

src/opts/SkNx_sse.h

Index: src/opts/SkNx_sse.h
diff --git a/src/opts/SkNx_sse.h b/src/opts/SkNx_sse.h
index 1fc235d99be4793bf9c9cffa906ccd0bfa39155e..80c7f0e9ae79f1a0e0743d77eb50a0fdbfb9a499 100644
--- a/src/opts/SkNx_sse.h
+++ b/src/opts/SkNx_sse.h
@@ -8,12 +8,20 @@
 #ifndef SkNx_sse_DEFINED
 #define SkNx_sse_DEFINED
 
-#include "SkCpu.h"
-
 // This file may assume <= SSE2, but must check SK_CPU_SSE_LEVEL for anything more recent.
 // If you do, make sure this is in a static inline function... anywhere else risks violating ODR.
 
 #define SKNX_IS_FAST
+
+// SSE 4.1 has _mm_floor_ps to floor 4 floats.  We emulate it:
+//   - roundtrip through integers via truncation
+//   - subtract 1 if that's too big (possible for negative values).
+// This restricts the domain of our inputs to a maximum somehwere around 2^31.  Seems plenty big.
+static inline __m128 sse2_mm_floor_ps(__m128 v) {
+    __m128 roundtrip = _mm_cvtepi32_ps(_mm_cvttps_epi32(v));
+    __m128 too_big = _mm_cmpgt_ps(roundtrip, v);
+    return _mm_sub_ps(roundtrip, _mm_and_ps(too_big, _mm_set1_ps(1.0f)));
+}
 
 template <>
 class SkNx<2, float> {
@@ -89,25 +97,7 @@
     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 floor() const {
-        if (SkCpu::Supports(SkCpu::SSE41)) {
-            __m128 r;
-        #if defined(__GNUC__) || defined(__clang__)
-            asm("roundps $0x1, %[fVec], %[r]" : [r]"=x"(r) : [fVec]"x"(fVec));
-        #else
-            r = _mm_floor_ps(fVec);
-        #endif
-            return r;
-        }
-        // Emulate _mm_floor_ps() with SSE2:
-        //   - roundtrip through integers via truncation
-        //   - subtract 1 if that's too big (possible for negative values).
-        // This restricts the domain of our inputs to a maximum somehwere around 2^31.
-        // Seems plenty big.
-        __m128 roundtrip = _mm_cvtepi32_ps(_mm_cvttps_epi32(fVec));
-        __m128 too_big = _mm_cmpgt_ps(roundtrip, fVec);
-        return _mm_sub_ps(roundtrip, _mm_and_ps(too_big, _mm_set1_ps(1.0f)));
-    }
+    SkNx floor() const { return sse2_mm_floor_ps(fVec); }
 
     SkNx   sqrt() const { return _mm_sqrt_ps (fVec);  }
     SkNx  rsqrt() const { return _mm_rsqrt_ps(fVec); }