Use __builtin_assume_aligned on untagged Lisp vals

[gnu-emacs] / src / conf_post.h

diff --git a/src/conf_post.h b/src/conf_post.h
index bea2a8a587f2ae3864d14c37b48087fcd420f3cb..762aa7727fd5f1ead4b572c0df21b75050dd24a0 100644 (file)
--- a/src/conf_post.h
+++ b/src/conf_post.h
@@ -64,6 +64,15 @@ typedef bool bool_bf;
     (4 < __GNUC__ + (8 <= __GNUC_MINOR__))
 #endif
 
+/* Simulate __has_builtin on compilers that lack it.  It is used only
+   on arguments like __builtin_assume_aligned that are handled in this
+   simulation.  */
+#ifndef __has_builtin
+# define __has_builtin(a) __has_builtin_##a
+# define __has_builtin___builtin_assume_aligned \
+    (4 < __GNUC__ + (7 <= __GNUC_MINOR__))
+#endif
+
 /* Simulate __has_feature on compilers that lack it.  It is used only
    to define ADDRESS_SANITIZER below.  */
 #ifndef __has_feature
@@ -77,6 +86,11 @@ typedef bool bool_bf;
 # define ADDRESS_SANITIZER false
 #endif
 
+/* Yield PTR, which must be aligned to ALIGNMENT.  */
+#if ! __has_builtin (__builtin_assume_aligned)
+# define __builtin_assume_aligned(ptr, alignment, ...) ((void *) (ptr))
+#endif
+
 #ifdef DARWIN_OS
 #ifdef emacs
 #define malloc unexec_malloc