diff mbox series

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

Message ID 20210717014121.1784956-3-richard.henderson@linaro.org
State New
Headers show
Series Atomic cleanup + clang-12 build fix | expand

Commit Message

Richard Henderson July 17, 2021, 1:41 a.m. UTC 
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(-)

-- 
2.25.1
diff mbox series

Patch

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 */