1 files changed, 47 insertions, 0 deletions
diff --git a/contrib/llvm-project/compiler-rt/lib/builtins/mulvsi3.c b/contrib/llvm-project/compiler-rt/lib/builtins/mulvsi3.c
new file mode 100644
index 000000000000..0d6b18ad01a4
--- /dev/null
+++ b/contrib/llvm-project/compiler-rt/lib/builtins/mulvsi3.c
@@ -0,0 +1,47 @@
+//===-- mulvsi3.c - Implement __mulvsi3 -----------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements __mulvsi3 for the compiler_rt library.
+//
+//===----------------------------------------------------------------------===//
+
+#include "int_lib.h"
+
+// Returns: a * b
+
+// Effects: aborts if a * b overflows
+
+COMPILER_RT_ABI si_int __mulvsi3(si_int a, si_int b) {
+  const int N = (int)(sizeof(si_int) * CHAR_BIT);
+  const si_int MIN = (si_int)1 << (N - 1);
+  const si_int MAX = ~MIN;
+  if (a == MIN) {
+    if (b == 0 || b == 1)
+      return a * b;
+    compilerrt_abort();
+  }
+  if (b == MIN) {
+    if (a == 0 || a == 1)
+      return a * b;
+    compilerrt_abort();
+  }
+  si_int sa = a >> (N - 1);
+  si_int abs_a = (a ^ sa) - sa;
+  si_int sb = b >> (N - 1);
+  si_int abs_b = (b ^ sb) - sb;
+  if (abs_a < 2 || abs_b < 2)
+    return a * b;
+  if (sa == sb) {
+    if (abs_a > MAX / abs_b)
+      compilerrt_abort();
+  } else {
+    if (abs_a > MIN / -abs_b)
+      compilerrt_abort();
+  }
+  return a * b;
+}