Extend fallthrough safety to LLVM in gmpy2_mpmath.c

The current fallthrough comments only suppress warnings for GCC. `__attribute__((fallthrough));` works for both GCC (>=7) and LLVM. C23 will introduce `[[fallthrough]]`.
aleaxit · Aug 6, 2024 · c0f1ed9 · c0f1ed9
1 parent 7bd27fe
commit c0f1ed9
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Showing 2 changed files with 16 additions and 3 deletions.
diff --git a/src/gmpy2_macros.h b/src/gmpy2_macros.h
@@ -726,3 +726,14 @@ GMPy_Context_##NAME(PyObject *self, PyObject *args) \
     } \
     return GMPy_Number_##NAME(PyTuple_GET_ITEM(args, 0), PyTuple_GET_ITEM(args, 1), context); \
 }
+
+/*********************************************************************/
+
+#if defined(__has_attribute)
+#  if __has_attribute(fallthrough)
+#    define GMPY_FALLTHROUGH __attribute__((fallthrough))
+#  endif
+#endif
+#if !defined(GMPY_FALLTHROUGH) 
+#  define GMPY_FALLTHROUGH (void)0
+#endif
diff --git a/src/gmpy2_mpmath.c b/src/gmpy2_mpmath.c
@@ -27,6 +27,8 @@
 
 /* Internal helper function for mpmath. */
 
+#include "gmpy2_macros.h"
+
 static PyObject *
 mpmath_build_mpf(long sign, MPZ_Object *man, PyObject *exp, mp_bitcnt_t bc)
 {
@@ -287,17 +289,17 @@ Pympz_mpmath_create_fast(PyObject *self, PyObject *const *args, Py_ssize_t nargs
     switch (nargs) {
         case 4:
             rnd = PyString_1Char(args[3]);
-            /* fallthrough */
+            GMPY_FALLTHROUGH;
         case 3:
             prec = GMPy_Integer_AsLong(args[2]);
             if (prec == (mp_bitcnt_t)(-1)) {
                 VALUE_ERROR("could not convert prec to positive int");
                 return NULL;
             }
-            /* fallthrough */
+            GMPY_FALLTHROUGH;
         case 2:
             exp = args[1];
-            /* fallthrough */
+            GMPY_FALLTHROUGH;
         case 1:
             man = GMPy_MPZ_From_Integer(args[0], NULL);
             if (!man) {