commit 5ed5d56d36fc50627edf537c75afa0fdf6ba4f5d
Author: Jeff Law <law@redhat.com>
Date:   Wed Nov 22 12:02:50 2017 -0700

    2017-10-31  Segher Boessenkool  <segher@kernel.crsahing.org>
    
           PR target/82674
           * config/rs6000/rs6000.md (allocate_stack): Force update interval
           into a register if it does not fit into an immediate offset field.

diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index 843148e9703..4b9732a78ec 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -10450,6 +10450,9 @@
 	{
 	  rtx loop_lab, end_loop;
 	  bool rotated = CONST_INT_P (rounded_size);
+	  rtx update = GEN_INT (-probe_interval);
+	  if (probe_interval > 32768)
+	    update = force_reg (Pmode, update);
 
 	  emit_stack_clash_protection_probe_loop_start (&loop_lab, &end_loop,
 							last_addr, rotated);
@@ -10457,13 +10460,11 @@
 	  if (Pmode == SImode)
 	    emit_insn (gen_movsi_update_stack (stack_pointer_rtx,
 					       stack_pointer_rtx,
-					       GEN_INT (-probe_interval),
-					       chain));
+					       update, chain));
 	  else
 	    emit_insn (gen_movdi_di_update_stack (stack_pointer_rtx,
 					          stack_pointer_rtx,
-					          GEN_INT (-probe_interval),
-					          chain));
+					          update, chain));
 	  emit_stack_clash_protection_probe_loop_end (loop_lab, end_loop,
 						      last_addr, rotated);
 	}