[libcxx-commits] [PATCH] D59999: Allow the compiler to optimize `string == "literal string"`.

[Samuel Benzaquen via Phabricator via libcxx-commits]

sbenza updated this revision to Diff 198284.
sbenza added a comment.

Another option for the optimzation.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D59999/new/

https://reviews.llvm.org/D59999

Files:
  libcxx/include/string


Index: libcxx/include/string
===================================================================
--- libcxx/include/string
+++ libcxx/include/string
@@ -3882,6 +3882,18 @@
     return __rhs.compare(0, _String::npos, __lhs, __lhs_len) == 0;
 }
 
+template<>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const char* __lhs,
+           const string& __rhs) _NOEXCEPT
+{
+    _LIBCPP_ASSERT(__lhs != nullptr, "operator==(char*, basic_string): received nullptr");
+    size_t __lhs_len = strlen(__lhs);
+    if (__lhs_len != __rhs.size()) return false;
+    return memcmp(__rhs.data(), __lhs, __lhs_len) == 0;
+}
+
 template<class _CharT, class _Traits, class _Allocator>
 inline _LIBCPP_INLINE_VISIBILITY
 bool
@@ -3895,6 +3907,17 @@
     return __lhs.compare(0, _String::npos, __rhs, __rhs_len) == 0;
 }
 
+template <>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const string& __lhs,
+           const char* __rhs) _NOEXCEPT {
+    _LIBCPP_ASSERT(__rhs != nullptr, "operator==(basic_string, char*): received nullptr");
+    const size_t __rhs_len = strlen(__rhs);
+    if (__rhs_len != __lhs.size()) return false;
+    return memcmp(__lhs.data(), __rhs, __rhs_len) == 0;
+}
+
 template<class _CharT, class _Traits, class _Allocator>
 inline _LIBCPP_INLINE_VISIBILITY
 bool


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D59999.198284.patch
Type: text/x-patch
Size: 1285 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/libcxx-commits/attachments/20190506/60f803ca/attachment.bin>