[llvm] affd73a - MathExtras: MulOverflow: use builtin when available (NFC) (#95046)

[via llvm-commits]

Author: Arjun P
Date: 2024-06-11T09:43:56+01:00
New Revision: affd73aadb9611b8a10c8cced63ad4ae1a0a9161

URL: https://github.com/llvm/llvm-project/commit/affd73aadb9611b8a10c8cced63ad4ae1a0a9161
DIFF: https://github.com/llvm/llvm-project/commit/affd73aadb9611b8a10c8cced63ad4ae1a0a9161.diff

LOG: MathExtras: MulOverflow: use builtin when available (NFC) (#95046)

This matches the other two functions AddOverflow and SubOverflow.

Added: 
    

Modified: 
    llvm/include/llvm/Support/MathExtras.h

Removed: 
    


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diff  --git a/llvm/include/llvm/Support/MathExtras.h b/llvm/include/llvm/Support/MathExtras.h
index f0e4ee534ece3..adb5ba6e3dcc2 100644
--- a/llvm/include/llvm/Support/MathExtras.h
+++ b/llvm/include/llvm/Support/MathExtras.h
@@ -635,6 +635,9 @@ std::enable_if_t<std::is_signed_v<T>, T> SubOverflow(T X, T Y, T &Result) {
 /// result, returning true if an overflow ocurred.
 template <typename T>
 std::enable_if_t<std::is_signed_v<T>, T> MulOverflow(T X, T Y, T &Result) {
+#if __has_builtin(__builtin_mul_overflow)
+  return __builtin_mul_overflow(X, Y, &Result);
+#else
   // Perform the unsigned multiplication on absolute values.
   using U = std::make_unsigned_t<T>;
   const U UX = X < 0 ? (0 - static_cast<U>(X)) : static_cast<U>(X);
@@ -656,6 +659,7 @@ std::enable_if_t<std::is_signed_v<T>, T> MulOverflow(T X, T Y, T &Result) {
     return UX > (static_cast<U>(std::numeric_limits<T>::max()) + U(1)) / UY;
   else
     return UX > (static_cast<U>(std::numeric_limits<T>::max())) / UY;
+#endif
 }
 
 } // namespace llvm