S/390: Fix PR84332 ICE with stack clash protection

Our implementation of the stack probe requires the probe interval to
be used as displacement in an address operand.  The maximum probe
interval currently is 64k.  This would exceed short displacements.
Trim that value down to 4k if that happens.  This might result in too
many probes being generated only on the oldest supported machine level
z900.

gcc/ChangeLog:

2018-08-09  Andreas Krebbel  <krebbel@linux.ibm.com>

	PR target/84332
	* config/s390/s390.c (s390_option_override_internal): Reduce the
	stack-clash-protection-probe-interval param if it would be too big
	for z900.

gcc/testsuite/ChangeLog:

2018-08-09  Andreas Krebbel  <krebbel@linux.ibm.com>

	PR target/84332
	* gcc.target/s390/pr84332.c: New testcase.

From-SVN: r263441

gcc/ChangeLog

+2018-08-09  Andreas Krebbel  <krebbel@linux.ibm.com>
+
+	PR target/84332
+	* config/s390/s390.c (s390_option_override_internal): Reduce the
+	stack-clash-protection-probe-interval param if it would be too big
+	for z900.
+
 2018-08-08  Andreas Schwab  <schwab@linux-m68k.org>
 
 	PR target/46179

gcc/config/s390/s390.c

@@ -14983,6 +14983,17 @@ s390_option_override_internal (struct gcc_options *opts,
   else if (opts->x_s390_stack_guard)
     error ("-mstack-guard implies use of -mstack-size");
 
+  /* Our implementation of the stack probe requires the probe interval
+     to be used as displacement in an address operand.  The maximum
+     probe interval currently is 64k.  This would exceed short
+     displacements.  Trim that value down to 4k if that happens.  This
+     might result in too many probes being generated only on the
+     oldest supported machine level z900.  */
+  if (!DISP_IN_RANGE ((1 << PARAM_VALUE (PARAM_STACK_CLASH_PROTECTION_PROBE_INTERVAL))))
+    set_param_value ("stack-clash-protection-probe-interval", 12,
+		     opts->x_param_values,
+		     opts_set->x_param_values);
+
 #ifdef TARGET_DEFAULT_LONG_DOUBLE_128
   if (!TARGET_LONG_DOUBLE_128_P (opts_set->x_target_flags))
     opts->x_target_flags |= MASK_LONG_DOUBLE_128;

gcc/testsuite/ChangeLog

+2018-08-09  Andreas Krebbel  <krebbel@linux.ibm.com>
+
+	PR target/84332
+	* gcc.target/s390/pr84332.c: New testcase.
+
 2018-08-08  Andreas Schwab  <schwab@linux-m68k.org>
 
 	PR target/46179

gcc/testsuite/gcc.target/s390/pr84332.c

+/* { dg-do compile } */
+/* { dg-options "-march=z900 -fstack-clash-protection --param stack-clash-protection-probe-interval=16" } */
+
+struct b
+{
+  char a[65536];
+};
+
+void c (void) { struct b d; }