Add avx512bw detection code

unit_test/cpu_test.cc

 /*
  *  Copyright 2012 The LibYuv Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS. All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 26 matching lines @@
   int has_sse42 = TestCpuFlag(kCpuHasSSE42);
   printf("Has SSE4.2 %x\n", has_sse42);
   int has_avx = TestCpuFlag(kCpuHasAVX);
   printf("Has AVX %x\n", has_avx);
   int has_avx2 = TestCpuFlag(kCpuHasAVX2);
   printf("Has AVX2 %x\n", has_avx2);
   int has_erms = TestCpuFlag(kCpuHasERMS);
   printf("Has ERMS %x\n", has_erms);
   int has_fma3 = TestCpuFlag(kCpuHasFMA3);
   printf("Has FMA3 %x\n", has_fma3);
+  int has_avx3 = TestCpuFlag(kCpuHasAVX3);
+  printf("Has AVX3 %x\n", has_avx3);
   int has_mips = TestCpuFlag(kCpuHasMIPS);
   printf("Has MIPS %x\n", has_mips);
   int has_mips_dsp = TestCpuFlag(kCpuHasMIPS_DSP);
   printf("Has MIPS DSP %x\n", has_mips_dsp);
   int has_mips_dspr2 = TestCpuFlag(kCpuHasMIPS_DSPR2);
   printf("Has MIPS DSPR2 %x\n", has_mips_dspr2);
 }
 
 TEST_F(LibYUVBaseTest, TestCompilerHasAVX2) {
 #ifdef _MSC_VER
@@ skipping 72 matching lines @@
     EXPECT_EQ(kCpuHasNEON, ArmCpuCaps("../../unit_test/testdata/juno.txt"));
   } else {
     printf("WARNING: unable to load \"../../unit_test/testdata/arm_v7.txt\"\n");
   }
 #if defined(__linux__) && defined(__ARM_NEON__)
   EXPECT_EQ(kCpuHasNEON, ArmCpuCaps("/proc/cpuinfo"));
 #endif
 }
 
 }  // namespace libyuv