1 files changed, 49 insertions, 0 deletions
diff --git a/contrib/llvm-project/compiler-rt/lib/builtins/int_mulo_impl.inc b/contrib/llvm-project/compiler-rt/lib/builtins/int_mulo_impl.inc
new file mode 100644
index 000000000000..27e7c8c43d60
--- /dev/null
+++ b/contrib/llvm-project/compiler-rt/lib/builtins/int_mulo_impl.inc
@@ -0,0 +1,49 @@
+//===-- int_mulo_impl.inc - Implement __mulo[sdt]i4 ---------------*- C -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Helper used by __mulosi4, __mulodi4 and __muloti4.
+//
+//===----------------------------------------------------------------------===//
+
+#include "int_lib.h"
+
+// Returns: a * b
+
+// Effects: sets *overflow to 1  if a * b overflows
+
+static __inline fixint_t __muloXi4(fixint_t a, fixint_t b, int *overflow) {
+  const int N = (int)(sizeof(fixint_t) * CHAR_BIT);
+  const fixint_t MIN = (fixint_t)((fixuint_t)1 << (N - 1));
+  const fixint_t MAX = ~MIN;
+  *overflow = 0;
+  fixint_t result = (fixuint_t)a * b;
+  if (a == MIN) {
+    if (b != 0 && b != 1)
+      *overflow = 1;
+    return result;
+  }
+  if (b == MIN) {
+    if (a != 0 && a != 1)
+      *overflow = 1;
+    return result;
+  }
+  fixint_t sa = a >> (N - 1);
+  fixint_t abs_a = (a ^ sa) - sa;
+  fixint_t sb = b >> (N - 1);
+  fixint_t abs_b = (b ^ sb) - sb;
+  if (abs_a < 2 || abs_b < 2)
+    return result;
+  if (sa == sb) {
+    if (abs_a > MAX / abs_b)
+      *overflow = 1;
+  } else {
+    if (abs_a > MIN / -abs_b)
+      *overflow = 1;
+  }
+  return result;
+}