PATCH: stack pointer alignment problem

[Herman ten Brugge]

Hello,

I discovered a stack pointer alignment problem on the c4x target.
The code:

tst()
{
  tst1();
}

Gets compiled as:

_tst:
        addi    1,sp
        call    _tst1
        addi    -1,sp
        rets

We do not need stack pointer alignment on the c4x target so we
defined STACK_BOUNDARY=32 (same as BITS_PER_UNIT=32). The call
to the function combine_pending_stack_adjustment_and_call resulted
in a stack adjustment of 1 in this case. The values stack_pointer_delta,
unadjusted_args_size and pending_stack_adjust are all 0.
This resulted in unadjusted_alignment being 0 and that results
in a stack pointer adjustment of 1.
With the patch below this is fixed. The addi 1,sp and addi -1,sp
are removed.

	Herman.

2000-06-01 Herman A.J. ten Brugge <Haj.Ten.Brugge@net.HCC.nl>

	* calls.c: Only use preferred_unit_stack_boundary when it is > 1.

 
--- calls.c.org	Sun Jul 30 21:10:56 2000
+++ calls.c	Sun Jul 30 21:10:58 2000
@@ -1913,10 +1913,13 @@ combine_pending_stack_adjustment_and_cal
   adjustment = pending_stack_adjust;
   /* Push enough additional bytes that the stack will be aligned
      after the arguments are pushed.  */
-  if (unadjusted_alignment >= 0)
-    adjustment -= preferred_unit_stack_boundary - unadjusted_alignment;
-  else
-    adjustment += unadjusted_alignment;
+  if (preferred_unit_stack_boundary > 1)
+    {
+      if (unadjusted_alignment >= 0)
+        adjustment -= preferred_unit_stack_boundary - unadjusted_alignment;
+      else
+        adjustment += unadjusted_alignment;
+    }
   
   /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
      bytes after the call.  The right number is the entire