Index: configure.ac
==================================================================
--- configure.ac
+++ configure.ac
@@ -60,10 +60,34 @@
 
 dnl Enable hardening
 AX_CHECK_COMPILE_FLAG([-fstack-protector-all], [CFLAGS="$CFLAGS -fstack-protector-all"])
 AX_CHECK_COMPILE_FLAG([-fno-strict-overflow], [CFLAGS="$CFLAGS -fno-strict-overflow"])
 AC_DEFINE([_FORTIFY_SOURCE], [2], [Enable fortification])
+
+dnl Enable OpenMP, if available
+tcl_nano_openmp=''
+AX_CHECK_COMPILE_FLAG([-fopenmp], [
+	tcl_nano_openmp='-fopenmp'
+], [
+	AX_CHECK_COMPILE_FLAG([-xopenmp], [
+		tcl_nano_openmp='-xopenmp'
+	], [
+		AX_CHECK_COMPILE_FLAG([-openmp], [
+			tcl_nano_openmp='-openmp'
+		], [
+			AX_CHECK_COMPILE_FLAG([/openmp], [
+				tcl_nano_openmp='/openmp'
+			])
+		])
+	])
+])
+
+if test -n "${tcl_nano_openmp}"; then
+	CFLAGS="$CFLAGS ${tcl_nano_openmp}"
+
+	AC_DEFINE([NANO_TCL_HAVE_OPENMP], [1], [Define if you have support for OpenMP])
+fi
 
 dnl Random number generation mechanisms
 AC_CHECK_FUNC(getrandom,, [
 	AC_CHECK_FUNC(getentropy,, [
 		AC_CHECK_FUNC(CryptGenRandom)

Index: nano.c
==================================================================
--- nano.c
+++ nano.c
@@ -2,10 +2,13 @@
 #include <limits.h>
 #include <string.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <tcl.h>
+#ifdef NANO_TCL_HAVE_OPENMP
+#  include <omp.h>
+#endif
 
 #include "randombytes.h"
 #include "tweetnacl.h"
 #include "blake2.h"
 
@@ -414,10 +417,11 @@
 	unsigned int offset;
 	int work_valid;
 
 	memcpy(work, blockhash, sizeof(work));
 
+	#pragma omp target
 	while (1) {
 		work_valid = nano_validate_work(blockhash, work, workMin);
 		if (work_valid) {
 			break;
 		}