Rename HAVE_BUILTIN_SHUFFLEVECTOR to HAVE_EFFICIENT_BUILTIN_SHUFFLEVECTOR

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: gpshead

Python/pystrhex.c

@@ -36,7 +36,7 @@ _Py_hexlify_scalar(const unsigned char *src, Py_UCS1 *dst, Py_ssize_t len)
    adds a ton of complication. Who ever really hexes huge data?
    The 16-64 byte boosts align nicely with md5 - sha512 hexdigests.
 */
-#ifdef HAVE_BUILTIN_SHUFFLEVECTOR_AND_IT_IS_WORTH_USING
+#ifdef HAVE_EFFICIENT_BUILTIN_SHUFFLEVECTOR
 
 /* 128-bit vector of 16 unsigned bytes */
 typedef unsigned char v16u8 __attribute__((vector_size(16)));
@@ -109,7 +109,7 @@ _Py_hexlify_simd(const unsigned char *src, Py_UCS1 *dst, Py_ssize_t len)
     _Py_hexlify_scalar(src + i, dst, len - i);
 }
 
-#endif /* HAVE_BUILTIN_SHUFFLEVECTOR_AND_IT_IS_WORTH_USING */
+#endif /* HAVE_EFFICIENT_BUILTIN_SHUFFLEVECTOR */
 
 static PyObject *_Py_strhex_impl(const char* argbuf, const Py_ssize_t arglen,
                                  PyObject* sep, int bytes_per_sep_group,
@@ -189,7 +189,7 @@ static PyObject *_Py_strhex_impl(const char* argbuf, const Py_ssize_t arglen,
     unsigned char c;
 
     if (bytes_per_sep_group == 0) {
-#ifdef HAVE_BUILTIN_SHUFFLEVECTOR_AND_IT_IS_WORTH_USING
+#ifdef HAVE_EFFICIENT_BUILTIN_SHUFFLEVECTOR
         if (arglen >= 16) {
             // little vector units go brrrr...
             _Py_hexlify_simd((const unsigned char *)argbuf, retbuf, arglen);

configure

@@ -5043,9 +5043,10 @@ AC_LINK_IFELSE([
 ])
 
 AS_VAR_IF([ac_cv_builtin_shufflevector], [yes], [
-    AC_DEFINE([HAVE_BUILTIN_SHUFFLEVECTOR_AND_IT_IS_WORTH_USING], [1],
-              [Define if compiler supports __builtin_shufflevector with
-               128-bit vectors on an architecture with native SIMD])
+    AC_DEFINE([HAVE_EFFICIENT_BUILTIN_SHUFFLEVECTOR], [1],
+              [Define if compiler supports __builtin_shufflevector with 128-bit
+               vectors AND the target architecture has native SIMD (not just API
+               availability)])
 ])
 
 # --with-mimalloc

configure.ac

@@ -126,10 +126,6 @@
 /* Has builtin __atomic_load_n() and __atomic_store_n() functions */
 #undef HAVE_BUILTIN_ATOMIC
 
-/* Define if compiler supports __builtin_shufflevector with 128-bit vectors on
-   an architecture with native SIMD */
-#undef HAVE_BUILTIN_SHUFFLEVECTOR_AND_IT_IS_WORTH_USING
-
 /* Define to 1 if you have the <bzlib.h> header file. */
 #undef HAVE_BZLIB_H
 
@@ -328,6 +324,10 @@
 /* Define to 1 if you have the <editline/readline.h> header file. */
 #undef HAVE_EDITLINE_READLINE_H
 
+/* Define if compiler supports __builtin_shufflevector with 128-bit vectors
+   AND the target architecture has native SIMD (not just API availability) */
+#undef HAVE_EFFICIENT_BUILTIN_SHUFFLEVECTOR
+
 /* Define to 1 if you have the <endian.h> header file. */
 #undef HAVE_ENDIAN_H