diff -urpN a/gcc/config/rs6000/altivec.md b/gcc/config/rs6000/altivec.md
--- a/gcc/config/rs6000/altivec.md	2018-01-15 01:47:30.483964000 +0800
+++ b/gcc/config/rs6000/altivec.md	2019-09-09 00:01:25.770835633 +0800
@@ -74,9 +74,6 @@
    UNSPEC_VUNPACK_LO_SIGN_DIRECT
    UNSPEC_VUPKHPX
    UNSPEC_VUPKLPX
-   UNSPEC_DARN
-   UNSPEC_DARN_32
-   UNSPEC_DARN_RAW
    UNSPEC_DST
    UNSPEC_DSTT
    UNSPEC_DSTST
@@ -3770,21 +3767,21 @@
 
 (define_insn "darn_32"
   [(set (match_operand:SI 0 "register_operand" "=r")
-        (unspec:SI [(const_int 0)] UNSPEC_DARN_32))]
+        (unspec_volatile:SI [(const_int 0)] UNSPECV_DARN_32))]
   "TARGET_P9_MISC"
   "darn %0,0"
   [(set_attr "type" "integer")])
 
 (define_insn "darn_raw"
   [(set (match_operand:DI 0 "register_operand" "=r")
-        (unspec:DI [(const_int 0)] UNSPEC_DARN_RAW))]
+        (unspec_volatile:DI [(const_int 0)] UNSPECV_DARN_RAW))]
   "TARGET_P9_MISC && TARGET_64BIT"
   "darn %0,2"
   [(set_attr "type" "integer")])
 
 (define_insn "darn"
   [(set (match_operand:DI 0 "register_operand" "=r")
-        (unspec:DI [(const_int 0)] UNSPEC_DARN))]
+        (unspec_volatile:DI [(const_int 0)] UNSPECV_DARN))]
   "TARGET_P9_MISC && TARGET_64BIT"
   "darn %0,1"
   [(set_attr "type" "integer")])
diff -urpN a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
--- a/gcc/config/rs6000/rs6000.md	2018-01-21 21:32:58.843504000 +0800
+++ b/gcc/config/rs6000/rs6000.md	2019-09-08 23:53:13.122859153 +0800
@@ -163,6 +163,9 @@
    UNSPECV_EH_RR		; eh_reg_restore
    UNSPECV_ISYNC		; isync instruction
    UNSPECV_MFTB			; move from time base
+   UNSPECV_DARN			; darn 1 (deliver a random number)
+   UNSPECV_DARN_32		; darn 2
+   UNSPECV_DARN_RAW		; darn 0
    UNSPECV_NLGR			; non-local goto receiver
    UNSPECV_MFFS			; Move from FPSCR
    UNSPECV_MTFSF		; Move to FPSCR Fields