[libcxx-commits] [PATCH] D71214: [libc++] reduce <complex> parsing time

[Nikita Kniazev via Phabricator via libcxx-commits]

nick created this revision.
nick added reviewers: ldionne, mclow.lists, EricWF.
nick added a project: libc++.
Herald added subscribers: libcxx-commits, dexonsmith, christof.

Instead of including `<ios>` for `ios_base::failbit` simply get `failbit` member of the template argument.
Print directly to a stream instead of using intermediate `ostringstream`.

Parsing time: 874ms -> 164ms (-81%)


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D71214

Files:
  libcxx/include/complex


Index: libcxx/include/complex
===================================================================
--- libcxx/include/complex
+++ libcxx/include/complex
@@ -243,7 +243,7 @@
 #include <type_traits>
 #include <stdexcept>
 #include <cmath>
-#include <sstream>
+#include <iosfwd>
 #include <version>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@@ -1406,10 +1406,10 @@
                             __x = complex<_Tp>(__r, __i);
                         }
                         else
-                            __is.setstate(ios_base::failbit);
+                            __is.setstate(__is.failbit);
                     }
                     else
-                        __is.setstate(ios_base::failbit);
+                        __is.setstate(__is.failbit);
                 }
                 else if (__c == _CharT(')'))
                 {
@@ -1417,10 +1417,10 @@
                     __x = complex<_Tp>(__r, _Tp(0));
                 }
                 else
-                    __is.setstate(ios_base::failbit);
+                    __is.setstate(__is.failbit);
             }
             else
-                __is.setstate(ios_base::failbit);
+                __is.setstate(__is.failbit);
         }
         else
         {
@@ -1429,11 +1429,11 @@
             if (!__is.fail())
                 __x = complex<_Tp>(__r, _Tp(0));
             else
-                __is.setstate(ios_base::failbit);
+                __is.setstate(__is.failbit);
         }
     }
     else
-        __is.setstate(ios_base::failbit);
+        __is.setstate(__is.failbit);
     return __is;
 }
 
@@ -1441,12 +1441,7 @@
 basic_ostream<_CharT, _Traits>&
 operator<<(basic_ostream<_CharT, _Traits>& __os, const complex<_Tp>& __x)
 {
-    basic_ostringstream<_CharT, _Traits> __s;
-    __s.flags(__os.flags());
-    __s.imbue(__os.getloc());
-    __s.precision(__os.precision());
-    __s << '(' << __x.real() << ',' << __x.imag() << ')';
-    return __os << __s.str();
+    return __os << '(' << __x.real() << ',' << __x.imag() << ')';
 }
 
 #if _LIBCPP_STD_VER > 11


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