[PATCH v2 02/11] qemu/atomic: Simplify typeof_strip_qual

[Richard Henderson]

The right-hand side of the comma operator has the type quals
stripped without also undergoing implicit promotion.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 include/qemu/atomic.h | 41 ++++-------------------------------------
 1 file changed, 4 insertions(+), 37 deletions(-)

diff --git a/include/qemu/atomic.h b/include/qemu/atomic.h
index 99d6030095..55d75fc757 100644
--- a/include/qemu/atomic.h
+++ b/include/qemu/atomic.h
@@ -18,47 +18,14 @@
 /* Compiler barrier */
 #define barrier()   ({ asm volatile("" ::: "memory"); (void)0; })
 
-/* The variable that receives the old value of an atomically-accessed
+/*
+ * The variable that receives the old value of an atomically-accessed
  * variable must be non-qualified, because atomic builtins return values
  * through a pointer-type argument as in __atomic_load(&var, &old, MODEL).
  *
- * This macro has to handle types smaller than int manually, because of
- * implicit promotion.  int and larger types, as well as pointers, can be
- * converted to a non-qualified type just by applying a binary operator.
+ * Handle this by evaluating an expression involving the comma operator.
  */
-#define typeof_strip_qual(expr)                                                
    \
-  typeof(                                                                      
    \
-    __builtin_choose_expr(                                                     
    \
-      __builtin_types_compatible_p(typeof(expr), bool) ||                      
    \
-        __builtin_types_compatible_p(typeof(expr), const bool) ||              
    \
-        __builtin_types_compatible_p(typeof(expr), volatile bool) ||           
    \
-        __builtin_types_compatible_p(typeof(expr), const volatile bool),       
    \
-        (bool)1,                                                               
    \
-    __builtin_choose_expr(                                                     
    \
-      __builtin_types_compatible_p(typeof(expr), signed char) ||               
    \
-        __builtin_types_compatible_p(typeof(expr), const signed char) ||       
    \
-        __builtin_types_compatible_p(typeof(expr), volatile signed char) ||    
    \
-        __builtin_types_compatible_p(typeof(expr), const volatile signed 
char),    \
-        (signed char)1,                                                        
    \
-    __builtin_choose_expr(                                                     
    \
-      __builtin_types_compatible_p(typeof(expr), unsigned char) ||             
    \
-        __builtin_types_compatible_p(typeof(expr), const unsigned char) ||     
    \
-        __builtin_types_compatible_p(typeof(expr), volatile unsigned char) ||  
    \
-        __builtin_types_compatible_p(typeof(expr), const volatile unsigned 
char),  \
-        (unsigned char)1,                                                      
    \
-    __builtin_choose_expr(                                                     
    \
-      __builtin_types_compatible_p(typeof(expr), signed short) ||              
    \
-        __builtin_types_compatible_p(typeof(expr), const signed short) ||      
    \
-        __builtin_types_compatible_p(typeof(expr), volatile signed short) ||   
    \
-        __builtin_types_compatible_p(typeof(expr), const volatile signed 
short),   \
-        (signed short)1,                                                       
    \
-    __builtin_choose_expr(                                                     
    \
-      __builtin_types_compatible_p(typeof(expr), unsigned short) ||            
    \
-        __builtin_types_compatible_p(typeof(expr), const unsigned short) ||    
    \
-        __builtin_types_compatible_p(typeof(expr), volatile unsigned short) || 
    \
-        __builtin_types_compatible_p(typeof(expr), const volatile unsigned 
short), \
-        (unsigned short)1,                                                     
    \
-      (expr)+0))))))
+#define typeof_strip_qual(expr)   typeof((void)0, (expr))
 
 #ifdef __ATOMIC_RELAXED
 /* For C11 atomic ops */
-- 
2.25.1