x86emitter: Don't use xgetbv

All OSes now support AVX

common/include/x86emitter/x86_intrin.h

@@ -34,7 +34,6 @@
 
 #define cpuid __cpuid
 #define cpuidex __cpuidex
-#define xgetbv _xgetbv
 
 #else
 
@@ -50,21 +49,6 @@ static __inline__ __attribute__((always_inline)) void cpuid(int CPUInfo[], const
     __cpuid(InfoType, CPUInfo[0], CPUInfo[1], CPUInfo[2], CPUInfo[3]);
 }
 
-#if defined(__clang__) || __GNUC__ < 8 || (__GNUC__ == 8 && __GNUC_MINOR__ < 2)
-// _xgetbv on gcc 8.1 is broken (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85684).
-// It also isn't present on clang and earlier versions of gcc.
-static __inline__ __attribute__((always_inline)) unsigned long long xgetbv(unsigned int index)
-{
-    unsigned int eax, edx;
-    __asm__ __volatile__("xgetbv"
-                         : "=a"(eax), "=d"(edx)
-                         : "c"(index));
-    return ((unsigned long long)edx << 32) | eax;
-}
-#else
-#define xgetbv _xgetbv
-#endif
-
 #endif
 
 // Rotate instruction

common/src/x86emitter/cpudetect.cpp

@@ -297,12 +297,12 @@ void x86capabilities::Identify()
 
     if ((Flags2 >> 27) & 1) // OSXSAVE
     {
-        if ((xgetbv(0) & 6) == 6) // XFEATURE_ENABLED_MASK[2:1] = '11b' (XMM state and YMM state are enabled by OS).
-        {
-            hasAVX = (Flags2 >> 28) & 1; //avx
-            hasFMA = (Flags2 >> 12) & 1; //fma
-            hasAVX2 = (SEFlag >> 5) & 1; //avx2
-        }
+        // Note: In theory, we should use xgetbv to check OS support
+        // but all OSes we officially run under support it
+        // and its intrinsic requires extra compiler flags
+        hasAVX = (Flags2 >> 28) & 1; //avx
+        hasFMA = (Flags2 >> 12) & 1; //fma
+        hasAVX2 = (SEFlag >> 5) & 1; //avx2
     }
 
     hasBMI1 = (SEFlag >> 3) & 1;