From b635388a900206b673fc23b5442345236b84cd75 Mon Sep 17 00:00:00 2001
From: Jeremy Evans <code@jeremyevans.net>
Date: Thu, 24 Aug 2023 13:44:03 -0700
Subject: Check that __builtin_mul_overflow can handle long long

Fixes [Bug #17646]

Patch from xtkoba (Tee KOBAYASHI)
---
 configure.ac | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

(limited to 'configure.ac')

diff --git a/configure.ac b/configure.ac
index f71c2c2609..05dd41e79c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2224,6 +2224,27 @@ RUBY_CHECK_BUILTIN_FUNC(__builtin_types_compatible_p, [__builtin_types_compatibl
 RUBY_CHECK_BUILTIN_FUNC(__builtin_trap, [__builtin_trap()])
 RUBY_CHECK_BUILTIN_FUNC(__builtin_expect, [__builtin_expect(0, 0)])
 
+AS_IF([test "$rb_cv_builtin___builtin_mul_overflow" != no], [
+  AC_CACHE_CHECK(for __builtin_mul_overflow with long long arguments, rb_cv_use___builtin_mul_overflow_long_long, [
+    AC_LINK_IFELSE([AC_LANG_SOURCE([[
+#pragma clang optimize off
+
+int
+main(void)
+{
+    long long x = 0, y;
+    __builtin_mul_overflow(x, x, &y);
+
+    return 0;
+}
+]])],
+	rb_cv_use___builtin_mul_overflow_long_long=yes,
+	rb_cv_use___builtin_mul_overflow_long_long=no)])
+])
+AS_IF([test "$rb_cv_use___builtin_mul_overflow_long_long" = yes], [
+  AC_DEFINE(USE___BUILTIN_MUL_OVERFLOW_LONG_LONG, 1)
+])
+
 AS_IF([test "$ac_cv_func_qsort_r" != no], [
   AC_CACHE_CHECK(whether qsort_r is GNU version, rb_cv_gnu_qsort_r,
     [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
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