[libc-commits] [libc] [libc] Make BigInt bit_cast-able to compatible types (PR #75063)

[Guillaume Chatelet via libc-commits]

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@@ -952,6 +952,35 @@ struct make_signed<UInt<Bits>> : type_identity<Int<Bits>> {
                 "Number of bits in Int should be a multiple of 64.");
 };
 
+namespace internal {
+template <typename T> struct is_custom_uint : cpp::false_type {};
+template <size_t Bits> struct is_custom_uint<UInt<Bits>> : cpp::true_type {};
+} // namespace internal
+
+// bit_cast to UInt
+template <typename To, typename From,
+          typename = cpp::enable_if_t<internal::is_custom_uint<To>::value>,
+          typename = cpp::enable_if_t<sizeof(To) == sizeof(From)>,
+          typename = cpp::enable_if_t<cpp::is_trivially_copyable<From>::value>>
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gchatelet wrote:

So this was not possible to use a single `typename` for function discrimination. I added an extended explanation. Let me know if it works for you.

https://github.com/llvm/llvm-project/pull/75063