[libcxx-commits] [libcxx] [libc++] Make __is_seed_sequence a variable template (PR #195420)
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Sat May 2 08:06:50 PDT 2026
llvmorg-github-actions[bot] wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-libcxx
Author: Nikolas Klauser (philnik777)
<details>
<summary>Changes</summary>
This makes things a bit more readable and improves compile times a bit.
---
Full diff: https://github.com/llvm/llvm-project/pull/195420.diff
7 Files Affected:
- (modified) libcxx/include/__random/discard_block_engine.h (+4-5)
- (modified) libcxx/include/__random/independent_bits_engine.h (+2-2)
- (modified) libcxx/include/__random/is_seed_sequence.h (+2-4)
- (modified) libcxx/include/__random/linear_congruential_engine.h (+2-2)
- (modified) libcxx/include/__random/mersenne_twister_engine.h (+2-2)
- (modified) libcxx/include/__random/shuffle_order_engine.h (+4-5)
- (modified) libcxx/include/__random/subtract_with_carry_engine.h (+2-2)
``````````diff
diff --git a/libcxx/include/__random/discard_block_engine.h b/libcxx/include/__random/discard_block_engine.h
index 12d1ff318ccd2..a6e1997fc1c2d 100644
--- a/libcxx/include/__random/discard_block_engine.h
+++ b/libcxx/include/__random/discard_block_engine.h
@@ -64,10 +64,9 @@ class discard_block_engine {
_LIBCPP_HIDE_FROM_ABI explicit discard_block_engine(_Engine&& __e) : __e_(std::move(__e)), __n_(0) {}
#endif // _LIBCPP_CXX03_LANG
_LIBCPP_HIDE_FROM_ABI explicit discard_block_engine(result_type __sd) : __e_(__sd), __n_(0) {}
- template <
- class _Sseq,
- __enable_if_t<__is_seed_sequence<_Sseq, discard_block_engine>::value && !is_convertible<_Sseq, _Engine>::value,
- int> = 0>
+ template <class _Sseq,
+ __enable_if_t<__is_seed_sequence_v<_Sseq, discard_block_engine> && !is_convertible<_Sseq, _Engine>::value,
+ int> = 0>
_LIBCPP_HIDE_FROM_ABI explicit discard_block_engine(_Sseq& __q) : __e_(__q), __n_(0) {}
_LIBCPP_HIDE_FROM_ABI void seed() {
__e_.seed();
@@ -77,7 +76,7 @@ class discard_block_engine {
__e_.seed(__sd);
__n_ = 0;
}
- template <class _Sseq, __enable_if_t<__is_seed_sequence<_Sseq, discard_block_engine>::value, int> = 0>
+ template <class _Sseq, __enable_if_t<__is_seed_sequence_v<_Sseq, discard_block_engine>, int> = 0>
_LIBCPP_HIDE_FROM_ABI void seed(_Sseq& __q) {
__e_.seed(__q);
__n_ = 0;
diff --git a/libcxx/include/__random/independent_bits_engine.h b/libcxx/include/__random/independent_bits_engine.h
index 7484857049414..947ed1f55ddc9 100644
--- a/libcxx/include/__random/independent_bits_engine.h
+++ b/libcxx/include/__random/independent_bits_engine.h
@@ -94,12 +94,12 @@ class independent_bits_engine {
_LIBCPP_HIDE_FROM_ABI explicit independent_bits_engine(result_type __sd) : __e_(__sd) {}
template <
class _Sseq,
- __enable_if_t<__is_seed_sequence<_Sseq, independent_bits_engine>::value && !is_convertible<_Sseq, _Engine>::value,
+ __enable_if_t<__is_seed_sequence_v<_Sseq, independent_bits_engine> && !is_convertible<_Sseq, _Engine>::value,
int> = 0>
_LIBCPP_HIDE_FROM_ABI explicit independent_bits_engine(_Sseq& __q) : __e_(__q) {}
_LIBCPP_HIDE_FROM_ABI void seed() { __e_.seed(); }
_LIBCPP_HIDE_FROM_ABI void seed(result_type __sd) { __e_.seed(__sd); }
- template <class _Sseq, __enable_if_t<__is_seed_sequence<_Sseq, independent_bits_engine>::value, int> = 0>
+ template <class _Sseq, __enable_if_t<__is_seed_sequence_v<_Sseq, independent_bits_engine>, int> = 0>
_LIBCPP_HIDE_FROM_ABI void seed(_Sseq& __q) {
__e_.seed(__q);
}
diff --git a/libcxx/include/__random/is_seed_sequence.h b/libcxx/include/__random/is_seed_sequence.h
index c7171cff2eda0..8b675cccd4474 100644
--- a/libcxx/include/__random/is_seed_sequence.h
+++ b/libcxx/include/__random/is_seed_sequence.h
@@ -21,10 +21,8 @@
_LIBCPP_BEGIN_NAMESPACE_STD
template <class _Sseq, class _Engine>
-struct __is_seed_sequence {
- static _LIBCPP_CONSTEXPR const bool value =
- !is_convertible<_Sseq, typename _Engine::result_type>::value && !is_same<__remove_cv_t<_Sseq>, _Engine>::value;
-};
+inline const bool __is_seed_sequence_v =
+ !is_convertible<_Sseq, typename _Engine::result_type>::value && !is_same<__remove_cv_t<_Sseq>, _Engine>::value;
_LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__random/linear_congruential_engine.h b/libcxx/include/__random/linear_congruential_engine.h
index f74129d9b8ffe..e8d3425097e07 100644
--- a/libcxx/include/__random/linear_congruential_engine.h
+++ b/libcxx/include/__random/linear_congruential_engine.h
@@ -265,14 +265,14 @@ class linear_congruential_engine {
#else
_LIBCPP_HIDE_FROM_ABI explicit linear_congruential_engine(result_type __s = default_seed) { seed(__s); }
#endif
- template <class _Sseq, __enable_if_t<__is_seed_sequence<_Sseq, linear_congruential_engine>::value, int> = 0>
+ template <class _Sseq, __enable_if_t<__is_seed_sequence_v<_Sseq, linear_congruential_engine>, int> = 0>
_LIBCPP_HIDE_FROM_ABI explicit linear_congruential_engine(_Sseq& __q) {
seed(__q);
}
_LIBCPP_HIDE_FROM_ABI void seed(result_type __s = default_seed) {
seed(integral_constant<bool, __m == 0>(), integral_constant<bool, __c == 0>(), __s);
}
- template <class _Sseq, __enable_if_t<__is_seed_sequence<_Sseq, linear_congruential_engine>::value, int> = 0>
+ template <class _Sseq, __enable_if_t<__is_seed_sequence_v<_Sseq, linear_congruential_engine>, int> = 0>
_LIBCPP_HIDE_FROM_ABI void seed(_Sseq& __q) {
__seed(
__q,
diff --git a/libcxx/include/__random/mersenne_twister_engine.h b/libcxx/include/__random/mersenne_twister_engine.h
index b1d7e29f8043e..7e26e9987ed92 100644
--- a/libcxx/include/__random/mersenne_twister_engine.h
+++ b/libcxx/include/__random/mersenne_twister_engine.h
@@ -172,7 +172,7 @@ class mersenne_twister_engine {
#else
_LIBCPP_HIDE_FROM_ABI explicit mersenne_twister_engine(result_type __sd = default_seed) { seed(__sd); }
#endif
- template <class _Sseq, __enable_if_t<__is_seed_sequence<_Sseq, mersenne_twister_engine>::value, int> = 0>
+ template <class _Sseq, __enable_if_t<__is_seed_sequence_v<_Sseq, mersenne_twister_engine>, int> = 0>
_LIBCPP_HIDE_FROM_ABI explicit mersenne_twister_engine(_Sseq& __q) {
seed(__q);
}
@@ -182,7 +182,7 @@ class mersenne_twister_engine {
__x_[__i] = (__f * (__x_[__i - 1] ^ __rshift<__w - 2>(__x_[__i - 1])) + __i) & _Max;
__i_ = 0;
}
- template <class _Sseq, __enable_if_t<__is_seed_sequence<_Sseq, mersenne_twister_engine>::value, int> = 0>
+ template <class _Sseq, __enable_if_t<__is_seed_sequence_v<_Sseq, mersenne_twister_engine>, int> = 0>
_LIBCPP_HIDE_FROM_ABI void seed(_Sseq& __q) {
const unsigned __k = 1 + (__w - 1) / 32;
static_assert(__k <= 2);
diff --git a/libcxx/include/__random/shuffle_order_engine.h b/libcxx/include/__random/shuffle_order_engine.h
index 64d73033a1609..febce5c7198dc 100644
--- a/libcxx/include/__random/shuffle_order_engine.h
+++ b/libcxx/include/__random/shuffle_order_engine.h
@@ -88,10 +88,9 @@ class shuffle_order_engine {
_LIBCPP_HIDE_FROM_ABI explicit shuffle_order_engine(_Engine&& __e) : __e_(std::move(__e)) { __init(); }
#endif // _LIBCPP_CXX03_LANG
_LIBCPP_HIDE_FROM_ABI explicit shuffle_order_engine(result_type __sd) : __e_(__sd) { __init(); }
- template <
- class _Sseq,
- __enable_if_t<__is_seed_sequence<_Sseq, shuffle_order_engine>::value && !is_convertible<_Sseq, _Engine>::value,
- int> = 0>
+ template <class _Sseq,
+ __enable_if_t<__is_seed_sequence_v<_Sseq, shuffle_order_engine> && !is_convertible<_Sseq, _Engine>::value,
+ int> = 0>
_LIBCPP_HIDE_FROM_ABI explicit shuffle_order_engine(_Sseq& __q) : __e_(__q) {
__init();
}
@@ -103,7 +102,7 @@ class shuffle_order_engine {
__e_.seed(__sd);
__init();
}
- template <class _Sseq, __enable_if_t<__is_seed_sequence<_Sseq, shuffle_order_engine>::value, int> = 0>
+ template <class _Sseq, __enable_if_t<__is_seed_sequence_v<_Sseq, shuffle_order_engine>, int> = 0>
_LIBCPP_HIDE_FROM_ABI void seed(_Sseq& __q) {
__e_.seed(__q);
__init();
diff --git a/libcxx/include/__random/subtract_with_carry_engine.h b/libcxx/include/__random/subtract_with_carry_engine.h
index c2b17cc889769..cbff7c8fa18a2 100644
--- a/libcxx/include/__random/subtract_with_carry_engine.h
+++ b/libcxx/include/__random/subtract_with_carry_engine.h
@@ -86,14 +86,14 @@ class subtract_with_carry_engine {
#else
_LIBCPP_HIDE_FROM_ABI explicit subtract_with_carry_engine(result_type __sd = default_seed) { seed(__sd); }
#endif
- template <class _Sseq, __enable_if_t<__is_seed_sequence<_Sseq, subtract_with_carry_engine>::value, int> = 0>
+ template <class _Sseq, __enable_if_t<__is_seed_sequence_v<_Sseq, subtract_with_carry_engine>, int> = 0>
_LIBCPP_HIDE_FROM_ABI explicit subtract_with_carry_engine(_Sseq& __q) {
seed(__q);
}
_LIBCPP_HIDE_FROM_ABI void seed(result_type __sd = default_seed) {
seed(__sd, integral_constant<unsigned, 1 + (__w - 1) / 32>());
}
- template <class _Sseq, __enable_if_t<__is_seed_sequence<_Sseq, subtract_with_carry_engine>::value, int> = 0>
+ template <class _Sseq, __enable_if_t<__is_seed_sequence_v<_Sseq, subtract_with_carry_engine>, int> = 0>
_LIBCPP_HIDE_FROM_ABI void seed(_Sseq& __q) {
__seed(__q, integral_constant<unsigned, 1 + (__w - 1) / 32>());
}
``````````
</details>
https://github.com/llvm/llvm-project/pull/195420
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