combine-stack-adj.c (combine_stack_adjustments_for_block): Do nothing for stack…

combine-stack-adj.c (combine_stack_adjustments_for_block): Do nothing for stack adjustments with REG_STACK_CHECK.

	* combine-stack-adj.c (combine_stack_adjustments_for_block): Do
	nothing for stack adjustments with REG_STACK_CHECK.
	* sched-deps.c (parse_add_or_inc): Reject insns with
	REG_STACK_CHECK from dependency breaking.
	* config/i386/i386.c (pro_epilogue_adjust_stack): Return insn.
	(ix86_adjust_satck_and_probe_stack_clash): Add REG_STACK_NOTEs.
	* reg-notes.def (STACK_CHECK): New note.

	* gcc.target/i386/stack-check-11.c: New test.

From-SVN: r252999

gcc/ChangeLog

 2017-09-19  Jeff Law  <law@redhat.com>
 
+	* combine-stack-adj.c (combine_stack_adjustments_for_block): Do
+	nothing for stack adjustments with REG_STACK_CHECK.
+	* sched-deps.c (parse_add_or_inc): Reject insns with
+	REG_STACK_CHECK from dependency breaking.
+	* config/i386/i386.c (pro_epilogue_adjust_stack): Return insn.
+	(ix86_adjust_satck_and_probe_stack_clash): Add REG_STACK_NOTEs.
+	* reg-notes.def (STACK_CHECK): New note.
+
 	* config/i386/i386.c (ix86_adjust_stack_and_probe_stack_clash): New.
 	(ix86_expand_prologue): Dump stack clash info as needed.
 	Call ix86_adjust_stack_and_probe_stack_clash as needed.

gcc/combine-stack-adj.c

@@ -508,6 +508,8 @@ combine_stack_adjustments_for_block (basic_block bb)
 	continue;
 
       set = single_set_for_csa (insn);
+      if (set && find_reg_note (insn, REG_STACK_CHECK, NULL_RTX))
+	set = NULL_RTX;
       if (set)
 	{
 	  rtx dest = SET_DEST (set);

gcc/config/i386/i386.c

@@ -13547,7 +13547,7 @@ ix86_add_queued_cfa_restore_notes (rtx insn)
    zero if %r11 register is live and cannot be freely used and positive
    otherwise.  */
 
-static void
+static rtx
 pro_epilogue_adjust_stack (rtx dest, rtx src, rtx offset,
 			   int style, bool set_cfa)
 {
@@ -13638,6 +13638,7 @@ pro_epilogue_adjust_stack (rtx dest, rtx src, rtx offset,
       m->fs.sp_valid = valid;
       m->fs.sp_realigned = realigned;
     }
+  return insn;
 }
 
 /* Find an available register to be used as dynamic realign argument
@@ -13987,9 +13988,11 @@ ix86_adjust_stack_and_probe_stack_clash (const HOST_WIDE_INT size)
       for (i = probe_interval; i <= size; i += probe_interval)
 	{
 	  /* Allocate PROBE_INTERVAL bytes.  */
-	  pro_epilogue_adjust_stack (stack_pointer_rtx, stack_pointer_rtx,
-				     GEN_INT (-probe_interval), -1,
-				     m->fs.cfa_reg == stack_pointer_rtx);
+	  rtx insn
+	    = pro_epilogue_adjust_stack (stack_pointer_rtx, stack_pointer_rtx,
+					 GEN_INT (-PROBE_INTERVAL), -1,
+					 m->fs.cfa_reg == stack_pointer_rtx);
+	  add_reg_note (insn, REG_STACK_CHECK, const0_rtx);
 
 	  /* And probe at *sp.  */
 	  emit_stack_probe (stack_pointer_rtx);

gcc/reg-notes.def

@@ -224,6 +224,10 @@ REG_NOTE (ARGS_SIZE)
    pseudo reg.  */
 REG_NOTE (RETURNED)
 
+/* Indicates the instruction is a stack check probe that should not
+   be combined with other stack adjustments.  */
+REG_NOTE (STACK_CHECK)
+
 /* Used to mark a call with the function decl called by the call.
    The decl might not be available in the call due to splitting of the call
    insn.  This note is a SYMBOL_REF.  */

gcc/sched-deps.c

@@ -4714,6 +4714,11 @@ parse_add_or_inc (struct mem_inc_info *mii, rtx_insn *insn, bool before_mem)
   if (RTX_FRAME_RELATED_P (insn) || !pat)
     return false;
 
+  /* Do not allow breaking data dependencies for insns that are marked
+     with REG_STACK_CHECK.  */
+  if (find_reg_note (insn, REG_STACK_CHECK, NULL))
+    return false;
+
   /* Result must be single reg.  */
   if (!REG_P (SET_DEST (pat)))
     return false;

gcc/testsuite/ChangeLog

 2017-09-19  Jeff Law  <law@redhat.com>
 
+	* gcc.target/i386/stack-check-11.c: New test.
+
 	* gcc.dg/stack-check-4.c: New test.
 	* gcc.dg/stack-check-5.c: New test.
 	* gcc.dg/stack-check-6.c: New test.

gcc/testsuite/gcc.target/i386/stack-check-11.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fstack-clash-protection" } */
+/* { dg-require-effective-target supports_stack_clash_protection } */
+
+extern void arf (unsigned long int *, unsigned long int *);
+void
+frob ()
+{
+  unsigned long int num[859];
+  unsigned long int den[859];
+  arf (den, num);
+}
+
+/* { dg-final { scan-assembler-times "subq" 4 } } */
+/* { dg-final { scan-assembler-times "orq" 3 } } */
+