diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d7278c09f45..aff5491eb8f 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2017-11-24  Segher Boessenkool  <segher@kernel.crashing.org>
+
+	Backport from mainline
+	2017-11-17  Segher Boessenkool  <segher@kernel.crashing.org>
+
+	PR rtl-optimization/82621
+	* combine.c (try_combine): Do not split PARALLELs of two SETs if the
+	dest of one of those SETs is unused.
+
 2017-11-23  Oleg Endo  <olegendo@gcc.gnu.org>
 
 	Backport from mainline
diff --git a/gcc/combine.c b/gcc/combine.c
index fff1c7e7bd4..c6257f60488 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -2964,7 +2964,8 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0,
       && is_parallel_of_n_reg_sets (PATTERN (i2), 2)
       && can_split_parallel_of_n_reg_sets (i2, 2)
       && !reg_used_between_p (SET_DEST (XVECEXP (PATTERN (i2), 0, 0)), i2, i3)
-      && !reg_used_between_p (SET_DEST (XVECEXP (PATTERN (i2), 0, 1)), i2, i3))
+      && !reg_used_between_p (SET_DEST (XVECEXP (PATTERN (i2), 0, 1)), i2, i3)
+      && !find_reg_note (i2, REG_UNUSED, 0))
     {
       /* If there is no I1, there is no I0 either.  */
       i0 = i1;