diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ab759abefd3..bed397cb071 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,7 @@
+2017-10-23  Sebastian Perta  <sebastian.perta@renesas.com>
+
+	* config/rl78/rl78.md: New define_expand "subdi3".
+
 2017-10-23  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR target/82673
diff --git a/gcc/config/rl78/rl78.md b/gcc/config/rl78/rl78.md
index 105d9bef360..c53ca0ff98d 100644
--- a/gcc/config/rl78/rl78.md
+++ b/gcc/config/rl78/rl78.md
@@ -268,6 +268,16 @@
   DONE;"
 )
 
+(define_expand "subdi3"
+ [(set (match_operand:DI          0 "nonimmediate_operand" "")
+    (minus:DI (match_operand:DI 1 "general_operand"      "")
+         (match_operand:DI    2 "general_operand"      "")))
+   ]
+  ""
+  "rl78_emit_libcall (\"__subdi3\", MINUS, DImode, DImode, 3, operands);
+   DONE;"
+)
+
 (define_insn "subsi3_internal_virt"
   [(set (match_operand:SI           0 "nonimmediate_operand" "=v,&vm, vm")
 	(minus:SI (match_operand:SI 1 "general_operand"      "0, vim, vim")
diff --git a/libgcc/ChangeLog b/libgcc/ChangeLog
index 932d12d0aae..f137fdff90f 100644
--- a/libgcc/ChangeLog
+++ b/libgcc/ChangeLog
@@ -1,3 +1,8 @@
+2017-10-23  Sebastian Perta  <sebastian.perta@renesas.com>
+
+	* config/rl78/subdi3.S: New assembly file.
+	* config/rl78/t-rl78: Added subdi3.S to LIB2ADD.
+
 2017-10-13  Sebastian Perta  <sebastian.perta@renesas.com>
 
 	* config/rl78/adddi3.S: New assembly file.
diff --git a/libgcc/config/rl78/subdi3.S b/libgcc/config/rl78/subdi3.S
new file mode 100644
index 00000000000..f6fcaba89ac
--- /dev/null
+++ b/libgcc/config/rl78/subdi3.S
@@ -0,0 +1,58 @@
+;   Copyright (C) 2017 Free Software Foundation, Inc.
+;   Contributed by Sebastian Perta.
+;
+; This file is free software; you can redistribute it and/or modify it
+; under the terms of the GNU General Public License as published by the
+; Free Software Foundation; either version 3, or (at your option) any
+; later version.
+;
+; This file is distributed in the hope that it will be useful, but
+; WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+; General Public License for more details.
+;
+; Under Section 7 of GPL version 3, you are granted additional
+; permissions described in the GCC Runtime Library Exception, version
+; 3.1, as published by the Free Software Foundation.
+;
+; You should have received a copy of the GNU General Public License and
+; a copy of the GCC Runtime Library Exception along with this program;
+; see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+; <http://www.gnu.org/licenses/>.
+
+
+#include "vregs.h"
+
+    .text
+
+START_FUNC ___subdi3
+
+    movw  hl, sp       ; use HL-based addressing (allows for direct subw)
+
+    movw  ax, [hl+4]
+    subw  ax, [hl+12]
+    movw  r8, ax
+
+    mov   a, [hl+6]    ; middle bytes of the result are determined using 8-bit
+    subc  a, [hl+14]   ; SUBC insns which both account for and update the carry bit
+    mov   r10, a       ; (no SUBWC instruction is available)
+    mov   a, [hl+7]
+    subc  a, [hl+15]
+    mov   r11, a
+
+    mov   a, [hl+8]
+    subc  a, [hl+16]
+    mov   r12, a
+    mov   a, [hl+9]
+    subc  a, [hl+17]
+    mov   r13, a
+
+    movw  ax, [hl+10]
+    sknc               ; account for the possible carry from the
+    decw  ax           ; latest 8-bit operation
+    subw  ax, [hl+18]
+    movw  r14, ax
+
+    ret
+
+END_FUNC ___subdi3
diff --git a/libgcc/config/rl78/t-rl78 b/libgcc/config/rl78/t-rl78
index 61db78dd326..e035d58c09c 100644
--- a/libgcc/config/rl78/t-rl78
+++ b/libgcc/config/rl78/t-rl78
@@ -31,7 +31,8 @@ LIB2ADD = \
 	$(srcdir)/config/rl78/fpbit-sf.S \
 	$(srcdir)/config/rl78/fpmath-sf.S \
 	$(srcdir)/config/rl78/cmpsi2.S \
-	$(srcdir)/config/rl78/adddi3.S
+	$(srcdir)/config/rl78/adddi3.S \
+	$(srcdir)/config/rl78/subdi3.S
 
 LIB2FUNCS_EXCLUDE = _clzhi2 _clzsi2 _ctzhi2 _ctzsi2 \
   _popcounthi2 _popcountsi2 \