Optimize -mstackrealign.

gcc/

2009-10-30  H.J. Lu  <hongjiu.lu@intel.com>

	PR target/40836
	* cfgexpand.c (expand_stack_alignment): Call update_stack_boundary
	first.  Move assert on stack_alignment_estimated just before
	setting stack_realign_needed.
	(gimple_expand_cfg): Initialize stack_alignment_estimated to 0.
	Don't call update_stack_boundary.

	* config/i386/i386.c (ix86_minimum_incoming_stack_boundary): New.
	(verride_options): Don't check ix86_force_align_arg_pointer here.
	(ix86_function_ok_for_sibcall): Use it.
	(ix86_update_stack_boundary): Likewise.

	* config/i386/i386.h (STACK_REALIGN_DEFAULT): Update comments.

gcc/testsuite/

2009-10-30  H.J. Lu  <hongjiu.lu@intel.com>

	PR target/40838
	* gcc.target/i386/incoming-6.c: New.
	* gcc.target/i386/incoming-7.c: Likewise.
	* gcc.target/i386/incoming-8.c: Likewise.
	* gcc.target/i386/incoming-9.c: Likewise.
	* gcc.target/i386/incoming-10.c: Likewise.
	* gcc.target/i386/incoming-11.c: Likewise.
	* gcc.target/i386/incoming-12.c: Likewise.
	* gcc.target/i386/incoming-13.c: Likewise.
	* gcc.target/i386/incoming-14.c: Likewise.
	* gcc.target/i386/incoming-15.c: Likewise.
	* gcc.target/i386/pr37843-4.c: Likewise.

From-SVN: r153750

1 files changed, 16 insertions, 20 deletions

diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c
index fdc4de5..33e7579 100644
--- a/gcc/cfgexpand.c
+++ b/gcc/cfgexpand.c
@@ -3447,8 +3447,18 @@ expand_stack_alignment (void)
       || crtl->has_nonlocal_goto)
     crtl->need_drap = true;
 
-  gcc_assert (crtl->stack_alignment_needed
-	      <= crtl->stack_alignment_estimated);
+  /* Call update_stack_boundary here again to update incoming stack
+     boundary.  It may set incoming stack alignment to a different
+     value after RTL expansion.  TARGET_FUNCTION_OK_FOR_SIBCALL may
+     use the minimum incoming stack alignment to check if it is OK
+     to perform sibcall optimization since sibcall optimization will
+     only align the outgoing stack to incoming stack boundary.  */
+  if (targetm.calls.update_stack_boundary)
+    targetm.calls.update_stack_boundary ();
+
+  /* The incoming stack frame has to be aligned at least at
+     parm_stack_boundary.  */
+  gcc_assert (crtl->parm_stack_boundary <= INCOMING_STACK_BOUNDARY);
 
   /* Update crtl->stack_alignment_estimated and use it later to align
      stack.  We check PREFERRED_STACK_BOUNDARY if there may be non-call
@@ -3464,6 +3474,9 @@ expand_stack_alignment (void)
   if (preferred_stack_boundary > crtl->stack_alignment_needed)
     crtl->stack_alignment_needed = preferred_stack_boundary;
 
+  gcc_assert (crtl->stack_alignment_needed
+	      <= crtl->stack_alignment_estimated);
+
   crtl->stack_realign_needed
     = INCOMING_STACK_BOUNDARY < crtl->stack_alignment_estimated;
   crtl->stack_realign_tried = crtl->stack_realign_needed;
@@ -3540,7 +3553,7 @@ gimple_expand_cfg (void)
   targetm.expand_to_rtl_hook ();
   crtl->stack_alignment_needed = STACK_BOUNDARY;
   crtl->max_used_stack_slot_alignment = STACK_BOUNDARY;
-  crtl->stack_alignment_estimated = STACK_BOUNDARY;
+  crtl->stack_alignment_estimated = 0;
   crtl->preferred_stack_boundary = STACK_BOUNDARY;
   cfun->cfg->max_jumptable_ents = 0;
 
@@ -3604,23 +3617,6 @@ gimple_expand_cfg (void)
   if (crtl->stack_protect_guard)
     stack_protect_prologue ();
 
-  /* Update stack boundary if needed.  */
-  if (SUPPORTS_STACK_ALIGNMENT)
-    {
-      /* Call update_stack_boundary here to update incoming stack
-	 boundary before TARGET_FUNCTION_OK_FOR_SIBCALL is called.
-	 TARGET_FUNCTION_OK_FOR_SIBCALL needs to know the accurate
-	 incoming stack alignment to check if it is OK to perform
-	 sibcall optimization since sibcall optimization will only
-	 align the outgoing stack to incoming stack boundary.  */
-      if (targetm.calls.update_stack_boundary)
-	targetm.calls.update_stack_boundary ();
-      
-      /* The incoming stack frame has to be aligned at least at
-	 parm_stack_boundary.  */
-      gcc_assert (crtl->parm_stack_boundary <= INCOMING_STACK_BOUNDARY);
-    }
-
   expand_phi_nodes (&SA);
 
   /* Register rtl specific functions for cfg.  */