Revert "Cherry pick: fix AVX & AVX2 detection"

source/libvpx/vpx_ports/x86.h

Index: source/libvpx/vpx_ports/x86.h
diff --git a/source/libvpx/vpx_ports/x86.h b/source/libvpx/vpx_ports/x86.h
index 2a3ebbe22e8d942f3ef30c2a18799f57061a4c6a..81c2b8b873f34c1814a9f7baad04da0d03ad625d 100644
--- a/source/libvpx/vpx_ports/x86.h
+++ b/source/libvpx/vpx_ports/x86.h
@@ -13,7 +13,6 @@
 #define VPX_PORTS_X86_H_
 #include <stdlib.h>
 #include "vpx_config.h"
-#include "vpx/vpx_integer.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -105,37 +104,6 @@ void __cpuid(int CPUInfo[4], int info_type);
 #endif
 #endif /* end others */
 
-// NaCl has no support for xgetbv or the raw opcode.
-#if !defined(__native_client__) && (defined(__i386__) || defined(__x86_64__))
-static INLINE uint64_t xgetbv(void) {
-  const uint32_t ecx = 0;
-  uint32_t eax, edx;
-  // Use the raw opcode for xgetbv for compatibility with older toolchains.
-  __asm__ volatile (
-    ".byte 0x0f, 0x01, 0xd0\n"
-    : "=a"(eax), "=d"(edx) : "c" (ecx));
-  return ((uint64_t)edx << 32) | eax;
-}
-#elif (defined(_M_X64) || defined(_M_IX86)) && \
-      defined(_MSC_FULL_VER) && _MSC_FULL_VER >= 160040219  // >= VS2010 SP1
-#include <immintrin.h>
-#define xgetbv() _xgetbv(0)
-#elif defined(_MSC_VER) && defined(_M_IX86)
-static INLINE uint64_t xgetbv(void) {
-  uint32_t eax_, edx_;
-  __asm {
-    xor ecx, ecx  // ecx = 0
-    // Use the raw opcode for xgetbv for compatibility with older toolchains.
-    __asm _emit 0x0f __asm _emit 0x01 __asm _emit 0xd0
-    mov eax_, eax
-    mov edx_, edx
-  }
-  return ((uint64_t)edx_ << 32) | eax_;
-}
-#else
-#define xgetbv() 0U  // no AVX for older x64 or unrecognized toolchains.
-#endif
-
 #define HAS_MMX     0x01
 #define HAS_SSE     0x02
 #define HAS_SSE2    0x04
@@ -188,17 +156,14 @@ x86_simd_caps(void) {
 
   if (reg_ecx & BIT(19)) flags |= HAS_SSE4_1;
 
-  // bits 27 (OSXSAVE) & 28 (256-bit AVX)
-  if (reg_ecx & (BIT(27) | BIT(28))) {
-    if ((xgetbv() & 0x6) == 0x6) {
-      flags |= HAS_AVX;
+  if (reg_ecx & BIT(28)) flags |= HAS_AVX;
 
-      /* Get the leaf 7 feature flags. Needed to check for AVX2 support */
-      cpuid(7, 0, reg_eax, reg_ebx, reg_ecx, reg_edx);
+  /* Get the leaf 7 feature flags. Needed to check for AVX2 support */
+  reg_eax = 7;
+  reg_ecx = 0;
+  cpuid(7, 0, reg_eax, reg_ebx, reg_ecx, reg_edx);
 
-      if (reg_ebx & BIT(5)) flags |= HAS_AVX2;
-    }
-  }
+  if (reg_ebx & BIT(5)) flags |= HAS_AVX2;
 
   return flags & mask;
 }