[gcc r12-9866] aarch64: Simplify top of frame allocation

[Richard Sandiford <rsandifo@gcc.gnu.org>]

https://gcc.gnu.org/g:b47766614df3b9df878262efb2ad73aaac108363

commit r12-9866-gb47766614df3b9df878262efb2ad73aaac108363
Author: Richard Sandiford <richard.sandiford@arm.com>
Date:   Tue Sep 12 16:08:53 2023 +0100

    aarch64: Simplify top of frame allocation
    
    After previous patches, it no longer really makes sense to allocate
    the top of the frame in terms of varargs_and_saved_regs_size and
    saved_regs_and_above.
    
    gcc/
            * config/aarch64/aarch64.cc (aarch64_layout_frame): Simplify
            the allocation of the top of the frame.

Diff:
---
 gcc/config/aarch64/aarch64.cc | 23 ++++++++---------------
 1 file changed, 8 insertions(+), 15 deletions(-)

diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
index 97dd077844b4..81935852d5b2 100644
--- a/gcc/config/aarch64/aarch64.cc
+++ b/gcc/config/aarch64/aarch64.cc
@@ -8325,23 +8325,16 @@ aarch64_layout_frame (void)
 
   frame.saved_regs_size = offset - frame.bytes_below_saved_regs;
 
-  poly_int64 varargs_and_saved_regs_size
-    = frame.saved_regs_size + frame.saved_varargs_size;
-
-  poly_int64 saved_regs_and_above
-    = aligned_upper_bound (varargs_and_saved_regs_size
-			   + get_frame_size (),
-			   STACK_BOUNDARY / BITS_PER_UNIT);
-
-  frame.bytes_above_hard_fp
-    = saved_regs_and_above - frame.below_hard_fp_saved_regs_size;
+  offset += get_frame_size ();
+  offset = aligned_upper_bound (offset, STACK_BOUNDARY / BITS_PER_UNIT);
+  auto top_of_locals = offset;
 
-  /* Both these values are already aligned.  */
-  gcc_assert (multiple_p (frame.bytes_below_saved_regs,
-			  STACK_BOUNDARY / BITS_PER_UNIT));
-  frame.frame_size = saved_regs_and_above + frame.bytes_below_saved_regs;
+  offset += frame.saved_varargs_size;
+  gcc_assert (multiple_p (offset, STACK_BOUNDARY / BITS_PER_UNIT));
+  frame.frame_size = offset;
 
-  frame.bytes_above_locals = frame.saved_varargs_size;
+  frame.bytes_above_hard_fp = frame.frame_size - frame.bytes_below_hard_fp;
+  frame.bytes_above_locals = frame.frame_size - top_of_locals;
 
   frame.initial_adjust = 0;
   frame.final_adjust = 0;