[libcxx-commits] [PATCH] D116487: [libc++][NFC] Introduce __fits_in_sso()

[Nikolas Klauser via Phabricator via libcxx-commits]

philnik updated this revision to Diff 397313.
philnik marked an inline comment as done.
philnik added a comment.

- Add comment to explain __libcpp_is_constant_evaluated() in __fits_in_sso()


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D116487/new/

https://reviews.llvm.org/D116487

Files:
  libcxx/include/string


Index: libcxx/include/string
===================================================================
--- libcxx/include/string
+++ libcxx/include/string
@@ -1455,6 +1455,11 @@
 #endif // _LIBCPP_DEBUG_LEVEL == 2
 
 private:
+    _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI static bool __fits_in_sso(size_type __sz) {
+        // SSO is disabled during constant evaluation because `__is_long` isn't constexpr friendly
+        return !__libcpp_is_constant_evaluated() && (__sz < __min_cap);
+    }
+
     _LIBCPP_INLINE_VISIBILITY
     allocator_type& __alloc() _NOEXCEPT
         {return __r_.second();}
@@ -1859,7 +1864,7 @@
     if (__reserve > max_size())
         this->__throw_length_error();
     pointer __p;
-    if (__reserve < __min_cap)
+    if (__fits_in_sso(__reserve))
     {
         __set_short_size(__sz);
         __p = __get_short_pointer();
@@ -1883,7 +1888,7 @@
     if (__sz > max_size())
         this->__throw_length_error();
     pointer __p;
-    if (__sz < __min_cap)
+    if (__fits_in_sso(__sz))
     {
         __set_short_size(__sz);
         __p = __get_short_pointer();
@@ -1975,7 +1980,7 @@
 void basic_string<_CharT, _Traits, _Allocator>::__init_copy_ctor_external(
     const value_type* __s, size_type __sz) {
   pointer __p;
-  if (__sz < __min_cap) {
+  if (__fits_in_sso(__sz)) {
     __p = __get_short_pointer();
     __set_short_size(__sz);
   } else {
@@ -2042,7 +2047,7 @@
     if (__n > max_size())
         this->__throw_length_error();
     pointer __p;
-    if (__n < __min_cap)
+    if (__fits_in_sso(__n))
     {
         __set_short_size(__n);
         __p = __get_short_pointer();
@@ -2194,7 +2199,7 @@
     if (__sz > max_size())
         this->__throw_length_error();
     pointer __p;
-    if (__sz < __min_cap)
+    if (__fits_in_sso(__sz))
     {
         __set_short_size(__sz);
         __p = __get_short_pointer();
@@ -2398,7 +2403,7 @@
 basic_string<_CharT, _Traits, _Allocator>::assign(const value_type* __s, size_type __n)
 {
     _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::assign received nullptr");
-    return (__builtin_constant_p(__n) && __n < __min_cap)
+    return (__builtin_constant_p(__n) && __fits_in_sso(__n))
                ? __assign_short(__s, __n)
                : __assign_external(__s, __n);
 }
@@ -2601,7 +2606,7 @@
 {
     _LIBCPP_ASSERT(__s != nullptr, "string::assign received nullptr");
     return __builtin_constant_p(*__s)
-               ? (traits_type::length(__s) < __min_cap
+               ? (__fits_in_sso(traits_type::length(__s))
                       ? __assign_short(__s, traits_type::length(__s))
                       : __assign_external(__s, traits_type::length(__s)))
                : __assign_external(__s);


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