blake2s: test all four hashing implementations

This adds use* flags for all arches so a common test can observe what
implementations are supported and test all supported implementations.

Change-Id: Icc9c3c1d15626e95f0446493b7fa3159bbe9567d
Reviewed-on: https://go-review.googlesource.com/31712
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: Andreas Auernhammer <aead@mail.de>

blake2s/blake2s_386.go

@@ -7,8 +7,10 @@
 package blake2s
 
 var (
-	useSSSE3 = supportSSSE3()
-	useSSE2  = supportSSE2()
+	useSSE4    = false
+	useSSSE3   = supportSSSE3()
+	useSSE2    = supportSSE2()
+	useGeneric = true
 )
 
 //go:noescape

blake2s/blake2s_amd64.go

@@ -7,8 +7,10 @@
 package blake2s
 
 var (
-	useSSE4  = supportSSE4()
-	useSSSE3 = supportSSSE3()
+	useSSE4    = supportSSE4()
+	useSSSE3   = supportSSSE3()
+	useSSE2    = true // Always available on amd64
+	useGeneric = false
 )
 
 //go:noescape

blake2s/blake2s_ref.go

@@ -6,6 +6,13 @@
 
 package blake2s
 
+var (
+	useSSE4    = false
+	useSSSE3   = false
+	useSSE2    = false
+	useGeneric = true
+)
+
 func hashBlocks(h *[8]uint32, c *[2]uint32, flag uint32, blocks []byte) {
 	hashBlocksGeneric(h, c, flag, blocks)
 }

blake2s/blake2s_test.go

@@ -11,6 +11,32 @@ import (
 )
 
 func TestHashes(t *testing.T) {
+	defer func(sse2, ssse3, sse4 bool) {
+		useSSE2, useSSSE3, useSSE4 = sse2, ssse3, sse4
+	}(useSSE2, useSSSE3, useSSE4)
+
+	if useSSE4 {
+		t.Log("SSE4 version")
+		testHashes(t)
+		useSSE4 = false
+	}
+	if useSSSE3 {
+		t.Log("SSSE3 version")
+		testHashes(t)
+		useSSSE3 = false
+	}
+	if useSSE2 {
+		t.Log("SSE2 version")
+		testHashes(t)
+		useSSE2 = false
+	}
+	if useGeneric {
+		t.Log("generic version")
+		testHashes(t)
+	}
+}
+
+func testHashes(t *testing.T) {
 	key, _ := hex.DecodeString("000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f")
 
 	input := make([]byte, 255)