[X86] Improve the unknown stepping support for Intel CPUs in getHostCPUName

[craig.topper]

Summary

This patch improves our guessing of unknown Intel CPUs to support Goldmont and skylake-avx512.

[igorb]

LGTM

[zvi]

Craig, do you plan on pushing this patch?

[craig.topper]

Yeah. I need to rebase it after by other changes to Host.cpp.

llvm/trunk/lib/Support/Host.cpp

enum ProcessorFeatures {
   FEATURE_AVX512VBMI,
   FEATURE_AVX512IFMA,
   FEATURE_AVX5124VNNIW,
   FEATURE_AVX5124FMAPS,
   FEATURE_AVX512VPOPCNTDQ,
   // Only one bit free left in the first 32 features.
   FEATURE_MOVBE = 32,
   FEATURE_ADX,
-  FEATURE_EM64T
+  FEATURE_EM64T,
+  FEATURE_CLFLUSHOPT,
+  FEATURE_SHA,
 };
 
 // The check below for i386 was copied from clang's cpuid.h (__get_cpuid_max).
 // Check motivated by bug reports for OpenSSL crashing on CPUs without CPUID
 // support. Consequently, for i386, the presence of CPUID is checked first
 // via the corresponding eflags bit.
 // Removal of cpuid.h header motivated by PR30384
 // Header cpuid.h and method __get_cpuid_max are not used in llvm, clang, openmp
case 0x5f:
       *Type = INTEL_GOLDMONT;
       break; // "goldmont"
     case 0x57:
       *Type = INTEL_KNL; // knl
       break;
 
     default: // Unknown family 6 CPU, try to guess.
       if (Features & (1 << FEATURE_AVX512F)) {
+        if (Features & (1 << FEATURE_AVX512VL)) {
+          *Type = INTEL_COREI7;
+          *Subtype = INTEL_COREI7_SKYLAKE_AVX512;
+        } else {
           *Type = INTEL_KNL; // knl
+        }
+        break;
+      }
+      if (Features2 & (1 << (FEATURE_CLFLUSHOPT - 32))) {
+        if (Features2 & (1 << (FEATURE_SHA - 32))) {
+          *Type = INTEL_GOLDMONT;
+        } else {
+          *Type = INTEL_COREI7;
+          *Subtype = INTEL_COREI7_SKYLAKE;
+        }
         break;
       }
       if (Features2 & (1 << (FEATURE_ADX - 32))) {
         *Type = INTEL_COREI7;
         *Subtype = INTEL_COREI7_BROADWELL;
         break;
       }
       if (Features & (1 << FEATURE_AVX2)) {
static void getAvailableFeatures(unsigned ECX, unsigned EDX, unsigned MaxLeaf,
   if (HasLeaf7 && ((EBX >> 16) & 1) && HasAVX512Save)
     Features |= 1 << FEATURE_AVX512F;
   if (HasLeaf7 && ((EBX >> 17) & 1) && HasAVX512Save)
     Features |= 1 << FEATURE_AVX512DQ;
   if (HasLeaf7 && ((EBX >> 19) & 1))
     Features2 |= 1 << (FEATURE_ADX - 32);
   if (HasLeaf7 && ((EBX >> 21) & 1) && HasAVX512Save)
     Features |= 1 << FEATURE_AVX512IFMA;
+  if (HasLeaf7 && ((EBX >> 23) & 1))
+    Features2 |= 1 << (FEATURE_CLFLUSHOPT - 32);
   if (HasLeaf7 && ((EBX >> 26) & 1) && HasAVX512Save)
     Features |= 1 << FEATURE_AVX512PF;
   if (HasLeaf7 && ((EBX >> 27) & 1) && HasAVX512Save)
     Features |= 1 << FEATURE_AVX512ER;
   if (HasLeaf7 && ((EBX >> 28) & 1) && HasAVX512Save)
     Features |= 1 << FEATURE_AVX512CD;
+  if (HasLeaf7 && ((EBX >> 29) & 1))
+    Features2 |= 1 << (FEATURE_SHA - 32);
   if (HasLeaf7 && ((EBX >> 30) & 1) && HasAVX512Save)
     Features |= 1 << FEATURE_AVX512BW;
   if (HasLeaf7 && ((EBX >> 31) & 1) && HasAVX512Save)
     Features |= 1 << FEATURE_AVX512VL;
 
   if (HasLeaf7 && ((ECX >> 1) & 1) && HasAVX512Save)
     Features |= 1 << FEATURE_AVX512VBMI;
   if (HasLeaf7 && ((ECX >> 14) & 1) && HasAVX512Save)