diff --git a/libgo/Makefile.am b/libgo/Makefile.am
index cf6975d2db9..f87494cac01 100644
--- a/libgo/Makefile.am
+++ b/libgo/Makefile.am
@@ -709,6 +709,9 @@ else
 if LIBGO_IS_SOLARIS
 go_os_sys_file = go/os/sys_uname.go
 else
+if LIBGO_IS_IRIX
+go_os_sys_file = go/os/sys_uname.go
+else
 if LIBGO_IS_RTEMS
 go_os_sys_file = go/os/sys_uname.go
 else
@@ -716,6 +719,7 @@ go_os_sys_file = go/os/sys_bsd.go
 endif
 endif
 endif
+endif
 
 go_os_files = \
 	$(go_os_dir_file) \
diff --git a/libgo/Makefile.in b/libgo/Makefile.in
index 306b9e43d43..e01f4f7f95e 100644
--- a/libgo/Makefile.in
+++ b/libgo/Makefile.in
@@ -1072,8 +1072,9 @@ go_netchan_files = \
 @LIBGO_IS_386_TRUE@@LIBGO_IS_SOLARIS_TRUE@go_os_dir_file = go/os/dir_largefile.go
 @LIBGO_IS_LINUX_FALSE@@LIBGO_IS_SOLARIS_FALSE@go_os_dir_file = go/os/dir_regfile.go
 @LIBGO_IS_LINUX_TRUE@@LIBGO_IS_SOLARIS_FALSE@go_os_dir_file = go/os/dir_largefile.go
-@LIBGO_IS_LINUX_FALSE@@LIBGO_IS_RTEMS_FALSE@@LIBGO_IS_SOLARIS_FALSE@go_os_sys_file = go/os/sys_bsd.go
-@LIBGO_IS_LINUX_FALSE@@LIBGO_IS_RTEMS_TRUE@@LIBGO_IS_SOLARIS_FALSE@go_os_sys_file = go/os/sys_uname.go
+@LIBGO_IS_IRIX_FALSE@@LIBGO_IS_LINUX_FALSE@@LIBGO_IS_RTEMS_FALSE@@LIBGO_IS_SOLARIS_FALSE@go_os_sys_file = go/os/sys_bsd.go
+@LIBGO_IS_IRIX_FALSE@@LIBGO_IS_LINUX_FALSE@@LIBGO_IS_RTEMS_TRUE@@LIBGO_IS_SOLARIS_FALSE@go_os_sys_file = go/os/sys_uname.go
+@LIBGO_IS_IRIX_TRUE@@LIBGO_IS_LINUX_FALSE@@LIBGO_IS_SOLARIS_FALSE@go_os_sys_file = go/os/sys_uname.go
 @LIBGO_IS_LINUX_FALSE@@LIBGO_IS_SOLARIS_TRUE@go_os_sys_file = go/os/sys_uname.go
 @LIBGO_IS_LINUX_TRUE@go_os_sys_file = go/os/sys_linux.go
 go_os_files = \
diff --git a/libgo/configure b/libgo/configure
index fbf6297b67b..e8f88f3c901 100644
--- a/libgo/configure
+++ b/libgo/configure
@@ -646,6 +646,8 @@ LIBGO_IS_RTEMS_FALSE
 LIBGO_IS_RTEMS_TRUE
 LIBGO_IS_LINUX_FALSE
 LIBGO_IS_LINUX_TRUE
+LIBGO_IS_IRIX_FALSE
+LIBGO_IS_IRIX_TRUE
 LIBGO_IS_FREEBSD_FALSE
 LIBGO_IS_FREEBSD_TRUE
 LIBGO_IS_DARWIN_FALSE
@@ -10902,7 +10904,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 10905 "configure"
+#line 10907 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -11008,7 +11010,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11011 "configure"
+#line 11013 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -13217,6 +13219,7 @@ fi
 
 is_darwin=no
 is_freebsd=no
+is_irix=no
 is_linux=no
 is_rtems=no
 is_solaris=no
@@ -13224,6 +13227,7 @@ GOOS=unknown
 case ${host} in
   *-*-darwin*)   is_darwin=yes;  GOOS=darwin ;;
   *-*-freebsd*)  is_freebsd=yes; GOOS=freebsd ;;
+  *-*-irix6*)    is_irix=yes;    GOOS=irix ;;
   *-*-linux*)    is_linux=yes;   GOOS=linux ;;
   *-*-rtems*)    is_rtems=yes;   GOOS=rtems ;;
   *-*-solaris2*) is_solaris=yes; GOOS=solaris ;;
@@ -13244,6 +13248,14 @@ else
   LIBGO_IS_FREEBSD_FALSE=
 fi
 
+ if test $is_irix = yes; then
+  LIBGO_IS_IRIX_TRUE=
+  LIBGO_IS_IRIX_FALSE='#'
+else
+  LIBGO_IS_IRIX_TRUE='#'
+  LIBGO_IS_IRIX_FALSE=
+fi
+
  if test $is_linux = yes; then
   LIBGO_IS_LINUX_TRUE=
   LIBGO_IS_LINUX_FALSE='#'
@@ -14497,6 +14509,10 @@ if test -z "${LIBGO_IS_FREEBSD_TRUE}" && test -z "${LIBGO_IS_FREEBSD_FALSE}"; th
   as_fn_error "conditional \"LIBGO_IS_FREEBSD\" was never defined.
 Usually this means the macro was only invoked conditionally." "$LINENO" 5
 fi
+if test -z "${LIBGO_IS_IRIX_TRUE}" && test -z "${LIBGO_IS_IRIX_FALSE}"; then
+  as_fn_error "conditional \"LIBGO_IS_IRIX\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
 if test -z "${LIBGO_IS_LINUX_TRUE}" && test -z "${LIBGO_IS_LINUX_FALSE}"; then
   as_fn_error "conditional \"LIBGO_IS_LINUX\" was never defined.
 Usually this means the macro was only invoked conditionally." "$LINENO" 5
diff --git a/libgo/configure.ac b/libgo/configure.ac
index 069635199d8..5bb5df4c1b9 100644
--- a/libgo/configure.ac
+++ b/libgo/configure.ac
@@ -114,6 +114,7 @@ AC_SUBST(LIBFFIINCS)
 
 is_darwin=no
 is_freebsd=no
+is_irix=no
 is_linux=no
 is_rtems=no
 is_solaris=no
@@ -121,12 +122,14 @@ GOOS=unknown
 case ${host} in
   *-*-darwin*)   is_darwin=yes;  GOOS=darwin ;;
   *-*-freebsd*)  is_freebsd=yes; GOOS=freebsd ;;
+  *-*-irix6*)    is_irix=yes;    GOOS=irix ;;
   *-*-linux*)    is_linux=yes;   GOOS=linux ;;
   *-*-rtems*)    is_rtems=yes;   GOOS=rtems ;;
   *-*-solaris2*) is_solaris=yes; GOOS=solaris ;;
 esac
 AM_CONDITIONAL(LIBGO_IS_DARWIN, test $is_darwin = yes)
 AM_CONDITIONAL(LIBGO_IS_FREEBSD, test $is_freebsd = yes)
+AM_CONDITIONAL(LIBGO_IS_IRIX, test $is_irix = yes)
 AM_CONDITIONAL(LIBGO_IS_LINUX, test $is_linux = yes)
 AM_CONDITIONAL(LIBGO_IS_RTEMS, test $is_rtems = yes)
 AM_CONDITIONAL(LIBGO_IS_SOLARIS, test $is_solaris = yes)
diff --git a/libgo/go/debug/proc/proc_irix.go b/libgo/go/debug/proc/proc_irix.go
new file mode 100644
index 00000000000..02c083911eb
--- /dev/null
+++ b/libgo/go/debug/proc/proc_irix.go
@@ -0,0 +1,17 @@
+// Copyright 2011 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proc
+
+import "os"
+
+// Process tracing is not supported on IRIX yet.
+
+func Attach(pid int) (Process, os.Error) {
+	return nil, os.NewError("debug/proc not implemented on IRIX")
+}
+
+func ForkExec(argv0 string, argv []string, envv []string, dir string, fd []*os.File) (Process, os.Error) {
+	return Attach(0)
+}
diff --git a/libgo/mksysinfo.sh b/libgo/mksysinfo.sh
index 331c04b9c37..abc583132dc 100755
--- a/libgo/mksysinfo.sh
+++ b/libgo/mksysinfo.sh
@@ -35,11 +35,23 @@ cat > sysinfo.c <<EOF
 #define __EXTENSIONS__
 #endif
 
+#ifdef __sgi__
+/* IRIX 6 needs _XOPEN_SOURCE=500 for the XPG5 version of struct msghdr in
+   <sys/socket.h>.  */
+#define _XOPEN_SOURCE 500
+#endif
+
 #include <sys/types.h>
 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <netinet/in.h>
+/* <netinet/tcp.h> needs u_char/u_short, but <sys/bsd_types> is only
+   included by <netinet/in.h> if _SGIAPI (i.e. _SGI_SOURCE
+   && !_XOPEN_SOURCE.  */
+#ifdef __sgi__
+#include <sys/bsd_types.h>
+#endif
 #include <netinet/tcp.h>
 #include <signal.h>
 #if defined(HAVE_SYSCALL_H)
@@ -81,13 +93,13 @@ echo 'package syscall' > ${OUT}
 grep -v '^// ' gen-sysinfo.go | \
   grep -v '^func' | \
   grep -v '^type _timeval ' | \
-  grep -v '^type _timespec ' | \
+  grep -v '^type _timespec\(_t\)\? ' | \
   grep -v '^type _timestruc_t ' | \
   grep -v '^type _epoll_' | \
   grep -v 'in6_addr' | \
   grep -v 'sockaddr_in6' | \
   sed -e 's/\([^a-zA-Z0-9_]\)_timeval\([^a-zA-Z0-9_]\)/\1Timeval\2/g' \
-      -e 's/\([^a-zA-Z0-9_]\)_timespec\([^a-zA-Z0-9_]\)/\1Timespec\2/g' \
+      -e 's/\([^a-zA-Z0-9_]\)_timespec\(_t\)\?\([^a-zA-Z0-9_]\)/\1Timespec\3/g' \
       -e 's/\([^a-zA-Z0-9_]\)_timestruc_t\([^a-zA-Z0-9_]\)/\1Timestruc\2/g' \
     >> ${OUT}
 
@@ -289,13 +301,17 @@ echo $timeval | \
   sed -e 's/type _timeval /type Timeval /' \
       -e 's/tv_sec *[a-zA-Z0-9_]*/Sec Timeval_sec_t/' \
       -e 's/tv_usec *[a-zA-Z0-9_]*/Usec Timeval_usec_t/' >> ${OUT}
-timespec=`grep '^type _timespec ' gen-sysinfo.go`
+timespec=`grep '^type _timespec ' gen-sysinfo.go || true`
+if test "$timespec" = ""; then
+  # IRIX 6.5 has __timespec instead.
+  timespec=`grep '^type ___timespec ' gen-sysinfo.go || true`
+fi
 timespec_sec=`echo $timespec | sed -n -e 's/^.*tv_sec \([^ ]*\);.*$/\1/p'`
 timespec_nsec=`echo $timespec | sed -n -e 's/^.*tv_nsec \([^ ]*\);.*$/\1/p'`
 echo "type Timespec_sec_t $timespec_sec" >> ${OUT}
 echo "type Timespec_nsec_t $timespec_nsec" >> ${OUT}
 echo $timespec | \
-  sed -e 's/^type _timespec /type Timespec /' \
+  sed -e 's/^type \(__\)\?_timespec /type Timespec /' \
       -e 's/tv_sec *[a-zA-Z0-9_]*/Sec Timespec_sec_t/' \
       -e 's/tv_nsec *[a-zA-Z0-9_]*/Nsec Timespec_nsec_t/' >> ${OUT}
 
@@ -333,7 +349,7 @@ fi | sed -e 's/type _stat\(64\)\?/type Stat_t/' \
          -e 's/st_mtim/Mtime/' \
          -e 's/st_ctim/Ctime/' \
          -e 's/\([^a-zA-Z0-9_]\)_timeval\([^a-zA-Z0-9_]\)/\1Timeval\2/g' \
-         -e 's/\([^a-zA-Z0-9_]\)_timespec\([^a-zA-Z0-9_]\)/\1Timespec\2/g' \
+         -e 's/\([^a-zA-Z0-9_]\)_timespec\(_t\)\?\([^a-zA-Z0-9_]\)/\1Timespec\3/g' \
          -e 's/\([^a-zA-Z0-9_]\)_timestruc_t\([^a-zA-Z0-9_]\)/\1Timestruc\2/g' \
        >> ${OUT}
 
diff --git a/libgo/syscalls/syscall_irix.go b/libgo/syscalls/syscall_irix.go
new file mode 100644
index 00000000000..e66cef045db
--- /dev/null
+++ b/libgo/syscalls/syscall_irix.go
@@ -0,0 +1,17 @@
+// syscall_irix.go -- IRIX 6 specific syscall interface.
+
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package syscall
+
+import "unsafe"
+
+// FIXME: ptrace(3C) has this, but exec.go expects the next.
+//func libc_ptrace(request int, pid Pid_t, addr int, data int) int __asm__ ("ptrace")
+
+func libc_ptrace(request int, pid Pid_t, addr uintptr, data *byte) int __asm__ ("ptrace")
+
+var dummy *byte
+const sizeofPtr uintptr = uintptr(unsafe.Sizeof(dummy))