Merge remote-tracking branch 'origin/v4' into v4

Author: pierrec

internal/lz4block/decode_amd64.s

@@ -157,24 +157,28 @@ copy_literal:
 	CMPQ BX, R8
 	JA err_short_buf
 
-	// whats a good cut off to call memmove?
-	CMPQ CX, $16
+	// Copy matches of <=48 bytes through the XMM registers.
+	CMPQ CX, $48
 	JGT memmove_lit
 
-	// if len(dst[di:]) < 16
+	// if len(dst[di:]) < 48
 	MOVQ R8, AX
 	SUBQ DI, AX
-	CMPQ AX, $16
+	CMPQ AX, $48
 	JLT memmove_lit
 
-	// if len(src[si:]) < 16
-	MOVQ R9, AX
-	SUBQ SI, AX
-	CMPQ AX, $16
+	// if len(src[si:]) < 48
+	MOVQ R9, BX
+	SUBQ SI, BX
+	CMPQ BX, $48
 	JLT memmove_lit
 
 	MOVOU (SI), X0
+	MOVOU 16(SI), X1
+	MOVOU 32(SI), X2
 	MOVOU X0, (DI)
+	MOVOU X1, 16(DI)
+	MOVOU X2, 32(DI)
 
 	ADDQ CX, SI
 	ADDQ CX, DI