[PATCH PR/34013]: Save red-zone while stack probing for x86_64

[Kai Tietz]

Hi,

I tested this and confirm the problem. I did a regression test of this 
patch for x86_64-linux and x86_64-mingw32 and it was successful.

ChangeLog

2007-12-13  Arthur Norman <acn1@cam.ac.uk>

        * gcc/config/i386/i386.c: (ix86_expand_prologue): Save red-zone 
while stack probing.


See bugzilla: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34013

--- i386.c.orig          2007-10-27 23:32:02.331569000 +0100
+++ i386.c               2007-11-09 22:27:25.695830000 +0000
@@ -6283,8 +6283,12 @@
     allocate += frame.nregs * UNITS_PER_WORD;
 
   /* When using red zone we may start register saving before allocating
-     the stack frame saving one cycle of the prologue.  */
-  if (TARGET_RED_ZONE && frame.save_regs_using_mov)
+     the stack frame saving one cycle of the prologue. However I will
+     avoid doing this if I am going to have to probe the stack since
+     at least on x86_64 the stack probe can turn into a call that 
clobbers
+     a red zone location */
+  if (TARGET_RED_ZONE && frame.save_regs_using_mov &&
+      (! TARGET_STACK_PROBE || allocate < CHECK_STACK_LIMIT))
     ix86_emit_save_regs_using_mov (frame_pointer_needed ? 
hard_frame_pointer_rtx
                                                                    : 
stack_pointer_rtx,
 -frame.nregs * UNITS_PER_WORD);
@@ -6340,7 +6344,8 @@
                 }
     }
 
-  if (frame.save_regs_using_mov && !TARGET_RED_ZONE)
+  if (frame.save_regs_using_mov && (!TARGET_RED_ZONE ||
+         !(! TARGET_STACK_PROBE || allocate < CHECK_STACK_LIMIT)))
     {
       if (!frame_pointer_needed || !frame.to_allocate)
         ix86_emit_save_regs_using_mov (stack_pointer_rtx, 
frame.to_allocate);

Cheers,
 i.A. Kai Tietz

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