[gcc r14-6734] untyped calls: use wrapper class type for implicit plus_one

[Alexandre Oliva]

https://gcc.gnu.org/g:438bf6ade4b089d592ec481086cde664a1ea1f3d

commit r14-6734-g438bf6ade4b089d592ec481086cde664a1ea1f3d
Author: Alexandre Oliva <oliva@adacore.com>
Date:   Wed Dec 20 04:59:00 2023 -0300

    untyped calls: use wrapper class type for implicit plus_one
    
    Instead of get and set macros to apply a delta, use a single macro
    that resorts to a temporary wrapper class to apply it.
    
    
    for  gcc/ChangeLog
    
            * builtins.cc (delta_type): New template class.
            (set_apply_args_size, get_apply_args_size): Replace with...
            (saved_apply_args_size): ... this.
            (set_apply_result_size, get_apply_result_size): Replace with...
            (saved_apply_result_size): ... this.
            (apply_args_size, apply_result_size): Adjust.

Diff:
---
 gcc/builtins.cc | 32 ++++++++++++++++++++------------
 1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/gcc/builtins.cc b/gcc/builtins.cc
index 7c2732ab79e..23cc6b6838a 100644
--- a/gcc/builtins.cc
+++ b/gcc/builtins.cc
@@ -1403,16 +1403,24 @@ get_memory_rtx (tree exp, tree len)
 

 /* Built-in functions to perform an untyped call and return.  */
 
-#define set_apply_args_size(x) \
-  (this_target_builtins->x_apply_args_size_plus_one = 1 + (x))
-#define get_apply_args_size() \
-  (this_target_builtins->x_apply_args_size_plus_one - 1)
+/* Wrapper that implicitly applies a delta when getting or setting the
+   enclosed value.  */
+template <typename T>
+class delta_type
+{
+  T &value; T const delta;
+public:
+  delta_type (T &val, T dlt) : value (val), delta (dlt) {}
+  operator T () const { return value + delta; }
+  T operator = (T val) const { value = val - delta; return val; }
+};
+
+#define saved_apply_args_size \
+  (delta_type<int> (this_target_builtins->x_apply_args_size_plus_one, -1))
 #define apply_args_mode \
   (this_target_builtins->x_apply_args_mode)
-#define set_apply_result_size(x) \
-  (this_target_builtins->x_apply_result_size_plus_one = 1 + (x))
-#define get_apply_result_size() \
-  (this_target_builtins->x_apply_result_size_plus_one - 1)
+#define saved_apply_result_size \
+  (delta_type<int> (this_target_builtins->x_apply_result_size_plus_one, -1))
 #define apply_result_mode \
   (this_target_builtins->x_apply_result_mode)
 
@@ -1422,7 +1430,7 @@ get_memory_rtx (tree exp, tree len)
 static int
 apply_args_size (void)
 {
-  int size = get_apply_args_size ();
+  int size = saved_apply_args_size;
   int align;
   unsigned int regno;
 
@@ -1456,7 +1464,7 @@ apply_args_size (void)
 	else
 	  apply_args_mode[regno] = as_a <fixed_size_mode> (VOIDmode);
 
-      set_apply_args_size (size);
+      saved_apply_args_size = size;
     }
   return size;
 }
@@ -1467,7 +1475,7 @@ apply_args_size (void)
 static int
 apply_result_size (void)
 {
-  int size = get_apply_result_size ();
+  int size = saved_apply_result_size;
   int align, regno;
 
   /* The values computed by this function never change.  */
@@ -1500,7 +1508,7 @@ apply_result_size (void)
       size = APPLY_RESULT_SIZE;
 #endif
 
-      set_apply_result_size (size);
+      saved_apply_result_size = size;
     }
   return size;
 }