* config/i386/i386.c (PROBE_INTERVAL): Remove.

	(get_probe_interval): New function.

	(ix86_adjust_stack_and_probe_stack_clash): Use get_probe_interval.

	(ix86_adjust_stack_and_probe): Likewise.

	(output_adjust_stack_and_probe): Likewise.

	(ix86_emit_probe_stack_range): Likewise.

	(ix86_expand_prologue): Likewise.

	* gcc.dg/pr82788.c: New test.

diff -Nrup a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c

--- a/gcc/config/i386/i386.c	2017-11-06 09:54:43.814921056 -0700

+++ b/gcc/config/i386/i386.c	2017-11-06 09:55:25.327589661 -0700

@@ -9839,7 +9839,17 @@ release_scratch_register_on_entry (struc

     }

 }

-#define PROBE_INTERVAL (1 << STACK_CHECK_PROBE_INTERVAL_EXP)

+/* Return the probing interval for -fstack-clash-protection.  */

+

+static HOST_WIDE_INT

+get_probe_interval (void)

+{

+  if (flag_stack_clash_protection)

+    return (HOST_WIDE_INT_1U

+	    << PARAM_VALUE (PARAM_STACK_CLASH_PROTECTION_PROBE_INTERVAL));

+  else

+    return (HOST_WIDE_INT_1U << STACK_CHECK_PROBE_INTERVAL_EXP);

+}

 /* Emit code to adjust the stack pointer by SIZE bytes while probing it.

@@ -9911,8 +9921,7 @@ ix86_adjust_stack_and_probe_stack_clash

   /* We're allocating a large enough stack frame that we need to

      emit probes.  Either emit them inline or in a loop depending

      on the size.  */

-  HOST_WIDE_INT probe_interval

-    = 1 << PARAM_VALUE (PARAM_STACK_CLASH_PROTECTION_PROBE_INTERVAL);

+  HOST_WIDE_INT probe_interval = get_probe_interval ();

   if (size <= 4 * probe_interval)

     {

       HOST_WIDE_INT i;

@@ -9921,7 +9930,7 @@ ix86_adjust_stack_and_probe_stack_clash

 	  /* Allocate PROBE_INTERVAL bytes.  */

 	  rtx insn

 	    = pro_epilogue_adjust_stack (stack_pointer_rtx, stack_pointer_rtx,

-					 GEN_INT (-PROBE_INTERVAL), -1,

+					 GEN_INT (-probe_interval), -1,

 					 m->fs.cfa_reg == stack_pointer_rtx);

 	  add_reg_note (insn, REG_STACK_CHECK, const0_rtx);

@@ -10014,7 +10023,7 @@ ix86_adjust_stack_and_probe (const HOST_

      that's the easy case.  The run-time loop is made up of 11 insns in the

      generic case while the compile-time loop is made up of 3+2*(n-1) insns

      for n # of intervals.  */

-  if (size <= 5 * PROBE_INTERVAL)

+  if (size <= 5 * get_probe_interval ())

     {

       HOST_WIDE_INT i, adjust;

       bool first_probe = true;

@@ -10023,15 +10032,15 @@ ix86_adjust_stack_and_probe (const HOST_

 	 values of N from 1 until it exceeds SIZE.  If only one probe is

 	 needed, this will not generate any code.  Then adjust and probe

 	 to PROBE_INTERVAL + SIZE.  */

-      for (i = PROBE_INTERVAL; i < size; i += PROBE_INTERVAL)

+      for (i = get_probe_interval (); i < size; i += get_probe_interval ())

 	{

 	  if (first_probe)

 	    {

-	      adjust = 2 * PROBE_INTERVAL + dope;

+	      adjust = 2 * get_probe_interval () + dope;

 	      first_probe = false;

 	    }

 	  else

-	    adjust = PROBE_INTERVAL;

+	    adjust = get_probe_interval ();

 	  emit_insn (gen_rtx_SET (VOIDmode, stack_pointer_rtx,

 				  plus_constant (Pmode, stack_pointer_rtx,

@@ -10040,9 +10049,9 @@ ix86_adjust_stack_and_probe (const HOST_

 	}

       if (first_probe)

-	adjust = size + PROBE_INTERVAL + dope;

+	adjust = size + get_probe_interval () + dope;

       else

-        adjust = size + PROBE_INTERVAL - i;

+        adjust = size + get_probe_interval () - i;

       emit_insn (gen_rtx_SET (VOIDmode, stack_pointer_rtx,

 			      plus_constant (Pmode, stack_pointer_rtx,

@@ -10052,7 +10061,8 @@ ix86_adjust_stack_and_probe (const HOST_

       /* Adjust back to account for the additional first interval.  */

       last = emit_insn (gen_rtx_SET (VOIDmode, stack_pointer_rtx,

 				     plus_constant (Pmode, stack_pointer_rtx,

-						    PROBE_INTERVAL + dope)));

+						    (get_probe_interval ()

+						     + dope))));

     }

   /* Otherwise, do the same as above, but in a loop.  Note that we must be

@@ -10070,7 +10080,7 @@ ix86_adjust_stack_and_probe (const HOST_

       /* Step 1: round SIZE to the previous multiple of the interval.  */

-      rounded_size = size & -PROBE_INTERVAL;

+      rounded_size = size & get_probe_interval ();

       /* Step 2: compute initial and final value of the loop counter.  */

@@ -10078,7 +10088,7 @@ ix86_adjust_stack_and_probe (const HOST_

       /* SP = SP_0 + PROBE_INTERVAL.  */

       emit_insn (gen_rtx_SET (VOIDmode, stack_pointer_rtx,

 			      plus_constant (Pmode, stack_pointer_rtx,

-					     - (PROBE_INTERVAL + dope))));

+					     - (get_probe_interval () + dope))));

       /* LAST_ADDR = SP_0 + PROBE_INTERVAL + ROUNDED_SIZE.  */

       emit_move_insn (sr.reg, GEN_INT (-rounded_size));

@@ -10115,7 +10125,8 @@ ix86_adjust_stack_and_probe (const HOST_

       /* Adjust back to account for the additional first interval.  */

       last = emit_insn (gen_rtx_SET (VOIDmode, stack_pointer_rtx,

 				     plus_constant (Pmode, stack_pointer_rtx,

-						    PROBE_INTERVAL + dope)));

+						    (get_probe_interval ()

+						     + dope))));

       release_scratch_register_on_entry (&sr);

     }

@@ -10134,7 +10145,7 @@ ix86_adjust_stack_and_probe (const HOST_

       XVECEXP (expr, 0, 1)

 	= gen_rtx_SET (VOIDmode, stack_pointer_rtx,

 		       plus_constant (Pmode, stack_pointer_rtx,

-				      PROBE_INTERVAL + dope + size));

+				      get_probe_interval () + dope + size));

       add_reg_note (last, REG_FRAME_RELATED_EXPR, expr);

       RTX_FRAME_RELATED_P (last) = 1;

@@ -10168,7 +10179,7 @@ output_adjust_stack_and_probe (rtx reg)

   fputc ('\n', asm_out_file);

   /* SP = SP + PROBE_INTERVAL.  */

-  xops[1] = GEN_INT (PROBE_INTERVAL);

+  xops[1] = GEN_INT (get_probe_interval ());

   output_asm_insn ("sub%z0\t{%1, %0|%0, %1}", xops);

   /* Probe at SP.  */

@@ -10194,14 +10205,14 @@ ix86_emit_probe_stack_range (HOST_WIDE_I

      that's the easy case.  The run-time loop is made up of 7 insns in the

      generic case while the compile-time loop is made up of n insns for n #

      of intervals.  */

-  if (size <= 7 * PROBE_INTERVAL)

+  if (size <= 7 * get_probe_interval ())

     {

       HOST_WIDE_INT i;

       /* Probe at FIRST + N * PROBE_INTERVAL for values of N from 1 until

 	 it exceeds SIZE.  If only one probe is needed, this will not

 	 generate any code.  Then probe at FIRST + SIZE.  */

-      for (i = PROBE_INTERVAL; i < size; i += PROBE_INTERVAL)

+      for (i = get_probe_interval (); i < size; i += get_probe_interval ())

 	emit_stack_probe (plus_constant (Pmode, stack_pointer_rtx,

 					 -(first + i)));

@@ -10224,7 +10235,7 @@ ix86_emit_probe_stack_range (HOST_WIDE_I

       /* Step 1: round SIZE to the previous multiple of the interval.  */

-      rounded_size = size & -PROBE_INTERVAL;

+      rounded_size = size & -get_probe_interval ();

       /* Step 2: compute initial and final value of the loop counter.  */

@@ -10291,7 +10302,7 @@ output_probe_stack_range (rtx reg, rtx e

   fputc ('\n', asm_out_file);

   /* TEST_ADDR = TEST_ADDR + PROBE_INTERVAL.  */

-  xops[1] = GEN_INT (PROBE_INTERVAL);

+  xops[1] = GEN_INT (get_probe_interval ());

   output_asm_insn ("sub%z0\t{%1, %0|%0, %1}", xops);

   /* Probe at TEST_ADDR.  */

diff -Nrup a/gcc/testsuite/gcc.dg/pr82788.c b/gcc/testsuite/gcc.dg/pr82788.c

--- a/gcc/testsuite/gcc.dg/pr82788.c	1969-12-31 17:00:00.000000000 -0700

+++ b/gcc/testsuite/gcc.dg/pr82788.c	2017-11-06 09:55:10.680706587 -0700

@@ -0,0 +1,4 @@

+/* { dg-do run } */

+/* { dg-options "-O2 -fstack-clash-protection --param stack-clash-protection-probe-interval=10 --param stack-clash-protection-guard-size=12" } */

+/* { dg-require-effective-target supports_stack_clash_protection } */

+int main() { int a[1442]; return 0;}