From 18883037a98240a7831c0d7c01dbe502fc5cfbd9 Mon Sep 17 00:00:00 2001 From: Benjamin Kramer Date: Sat, 28 Apr 2012 16:22:31 +0000 Subject: [PATCH] If the __is_trivially_copyable type trait is available use it as the baseline for isPodLike. This way we can enable the POD-like class optimization for a lot more classes, saving ~120k of code in clang/i386/Release+Asserts when selfhosting. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155761 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/Support/type_traits.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/include/llvm/Support/type_traits.h b/include/llvm/Support/type_traits.h index a3a551f851f..7b97547be52 100644 --- a/include/llvm/Support/type_traits.h +++ b/include/llvm/Support/type_traits.h @@ -21,6 +21,11 @@ #include #include +#ifndef __has_feature +#define LLVM_DEFINED_HAS_FEATURE +#define __has_feature(x) 0 +#endif + // This is actually the conforming implementation which works with abstract // classes. However, enough compilers have trouble with it that most will use // the one in boost/type_traits/object_traits.hpp. This implementation actually @@ -58,9 +63,15 @@ struct is_class /// type can be copied around with memcpy instead of running ctors etc. template struct isPodLike { +#if __has_feature(is_trivially_copyable) + // If the compiler supports the is_trivially_copyable trait use it, as it + // matches the definition of isPodLike closely. + static const bool value = __is_trivially_copyable(T); +#else // If we don't know anything else, we can (at least) assume that all non-class // types are PODs. static const bool value = !is_class::value; +#endif }; // std::pair's are pod-like if their elements are. @@ -202,4 +213,8 @@ struct conditional { typedef F type; }; } +#ifdef LLVM_DEFINED_HAS_FEATURE +#undef __has_feature +#endif + #endif