[dev.simd] internal/cpu: add GFNI feature check

This CL amends HasAVX512 flag with GFNI check.

This is needed because our SIMD API supports Galois Field operations.

Change-Id: I3e957b7b2215d2b7b6b8a7a0ca3e2e60d453b2e5
Reviewed-on: https://go-review.googlesource.com/c/go/+/685295
Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

src/internal/cpu/cpu.go

@@ -26,32 +26,34 @@ var CacheLineSize uintptr = CacheLinePadSize
 // in addition to the cpuid feature bit being set.
 // The struct is padded to avoid false sharing.
 var X86 struct {
-	_            CacheLinePad
+	_             CacheLinePad
-	HasAES       bool
+	HasAES        bool
-	HasADX       bool
+	HasADX        bool
-	HasAVX       bool
+	HasAVX        bool
-	HasAVX2      bool
+	HasAVX2       bool
-	HasAVX512    bool // Virtual feature: F+CD+BW+DQ+VL
+	HasAVX512GFNI bool // Virtual feature: F+CD+BW+DQ+VL+GFNI
-	HasAVX512F   bool
+	HasAVX512     bool // Virtual feature: F+CD+BW+DQ+VL
-	HasAVX512CD  bool
+	HasAVX512F    bool
-	HasAVX512BW  bool
+	HasAVX512CD   bool
-	HasAVX512DQ  bool
+	HasAVX512BW   bool
-	HasAVX512VL  bool
+	HasAVX512DQ   bool
-	HasBMI1      bool
+	HasAVX512VL   bool
-	HasBMI2      bool
+	HasBMI1       bool
-	HasERMS      bool
+	HasBMI2       bool
-	HasFSRM      bool
+	HasERMS       bool
-	HasFMA       bool
+	HasFSRM       bool
-	HasOSXSAVE   bool
+	HasFMA        bool
-	HasPCLMULQDQ bool
+	HasGFNI       bool
-	HasPOPCNT    bool
+	HasOSXSAVE    bool
-	HasRDTSCP    bool
+	HasPCLMULQDQ  bool
-	HasSHA       bool
+	HasPOPCNT     bool
-	HasSSE3      bool
+	HasRDTSCP     bool
-	HasSSSE3     bool
+	HasSHA        bool
-	HasSSE41     bool
+	HasSSE3       bool
-	HasSSE42     bool
+	HasSSSE3      bool
-	_            CacheLinePad
+	HasSSE41      bool
+	HasSSE42      bool
+	_             CacheLinePad
 }
 
 // The booleans in ARM contain the correspondingly named cpu feature bit.

src/internal/cpu/cpu_x86.go

@@ -22,6 +22,7 @@ const (
 	cpuid_SSE3      = 1 << 0
 	cpuid_PCLMULQDQ = 1 << 1
 	cpuid_SSSE3     = 1 << 9
+	cpuid_GFNI      = 1 << 8
 	cpuid_FMA       = 1 << 12
 	cpuid_SSE41     = 1 << 19
 	cpuid_SSE42     = 1 << 20
@@ -143,7 +144,7 @@ func doinit() {
 		return
 	}
 
-	_, ebx7, _, edx7 := cpuid(7, 0)
+	_, ebx7, ecx7, edx7 := cpuid(7, 0)
 	X86.HasBMI1 = isSet(ebx7, cpuid_BMI1)
 	X86.HasAVX2 = isSet(ebx7, cpuid_AVX2) && osSupportsAVX
 	X86.HasBMI2 = isSet(ebx7, cpuid_BMI2)
@@ -160,6 +161,7 @@ func doinit() {
 	}
 
 	X86.HasFSRM = isSet(edx7, cpuid_FSRM)
+	X86.HasGFNI = isSet(ecx7, cpuid_GFNI)
 
 	var maxExtendedInformation uint32
 	maxExtendedInformation, _, _, _ = cpuid(0x80000000, 0)
@@ -180,6 +182,7 @@ func doinit() {
 		// it. GOAMD64=v4 also implies exactly this set, and these are all
 		// included in AVX10.1.
 		X86.HasAVX512 = X86.HasAVX512F && X86.HasAVX512CD && X86.HasAVX512BW && X86.HasAVX512DQ && X86.HasAVX512VL
+		X86.HasAVX512GFNI = X86.HasAVX512 && X86.HasGFNI
 	}
 }
 

src/simd/cpu.go

@@ -11,6 +11,11 @@ package simd
 
 import "internal/cpu"
 
+// HasAVX512GFNI checks AVX512 CPU feature F+CD+BW+DQ+VL+GFNI.
+func HasAVX512GFNI() bool {
+	return cpu.X86.HasAVX512GFNI
+}
+
 // HasAVX512 checks AVX512 CPU feature F+CD+BW+DQ+VL.
 func HasAVX512() bool {
 	return cpu.X86.HasAVX512

src/simd/simd_test.go

@@ -38,7 +38,7 @@ func TestType(t *testing.T) {
 	v.y = &y
 	sink = y
 
-	if !simd.HasAVX512() {
+	if !simd.HasAVX512GFNI() {
 		t.Skip("Test requires HasAVX512, not available on this hardware")
 		return
 	}
@@ -97,7 +97,7 @@ func TestReflectMethod(t *testing.T) {
 }
 
 func TestVectorConversion(t *testing.T) {
-	if !simd.HasAVX512() {
+	if !simd.HasAVX512GFNI() {
 		t.Skip("Test requires HasAVX512, not available on this hardware")
 		return
 	}
@@ -115,7 +115,7 @@ func TestVectorConversion(t *testing.T) {
 }
 
 func TestMaskConversion(t *testing.T) {
-	if !simd.HasAVX512() {
+	if !simd.HasAVX512GFNI() {
 		t.Skip("Test requires HasAVX512, not available on this hardware")
 		return
 	}
@@ -144,7 +144,7 @@ func TestSub(t *testing.T) {
 }
 
 func TestMaskedAdd(t *testing.T) {
-	if !simd.HasAVX512() {
+	if !simd.HasAVX512GFNI() {
 		t.Skip("Test requires HasAVX512, not available on this hardware")
 		return
 	}