diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 1c81e4f5552..0acd815b35c 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2018-05-09  Segher Boessenkool  <segher@kernel.crashing.org>
+
+	PR rtl-optimization/85645
+	* config/rs6000/rs6000.c (rs6000_emit_prologue_components): Put a SET
+	in the REG_CFA_REGISTER note for LR, don't leave it empty.
+
 2018-05-09  Segher Boessenkool  <segher@kernel.crashing.org>
 
 	PR rtl-optimization/85645
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 6fb79f29a62..19913da9584 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -26151,10 +26151,11 @@ rs6000_emit_prologue_components (sbitmap components)
   /* Prologue for LR.  */
   if (bitmap_bit_p (components, 0))
     {
+      rtx lr = gen_rtx_REG (reg_mode, LR_REGNO);
       rtx reg = gen_rtx_REG (reg_mode, 0);
-      rtx_insn *insn = emit_move_insn (reg, gen_rtx_REG (reg_mode, LR_REGNO));
+      rtx_insn *insn = emit_move_insn (reg, lr);
       RTX_FRAME_RELATED_P (insn) = 1;
-      add_reg_note (insn, REG_CFA_REGISTER, NULL);
+      add_reg_note (insn, REG_CFA_REGISTER, gen_rtx_SET (reg, lr));
 
       int offset = info->lr_save_offset;
       if (info->push_p)
@@ -26162,7 +26163,6 @@ rs6000_emit_prologue_components (sbitmap components)
 
       insn = emit_insn (gen_frame_store (reg, ptr_reg, offset));
       RTX_FRAME_RELATED_P (insn) = 1;
-      rtx lr = gen_rtx_REG (reg_mode, LR_REGNO);
       rtx mem = copy_rtx (SET_DEST (single_set (insn)));
       add_reg_note (insn, REG_CFA_OFFSET, gen_rtx_SET (mem, lr));
     }