Subject: [PATCH] rs6000: Fix crash with big stack clash interval (PR82674)

If the user asks for a stack clash probe interval of 64kB, we currently
generate a "stdu rX,-65536(r1)" instruction.  That instruction does not
exist (the offset is a 16-bit signed number).  If the offset is too big
we should force it into a register and generate a "stdux rX,rY,r1"
instruction, instead.


	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.

From-SVN: r254252

gcc/ChangeLog

+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.
+
 2017-10-31  Olivier Hainque  <hainque@adacore.com>
 
         * gcc/Makefile.in (FLAGS_TO_PASS): Pass libsubdir as well.
 
-2017-11-01  Julia Koval  <julia.koval@intel.com>
+2017-10-31  Julia Koval  <julia.koval@intel.com>
 
 	* config.gcc: Add gfniintrin.h.
 	* config/i386/gfniintrin.h: New.

gcc/config/rs6000/rs6000.md

@@ -10333,6 +10333,9 @@
 	{
 	  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);
@@ -10340,13 +10343,11 @@
 	  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);
 	}