Extended Description

r207606 has broken stage2 bootstrap on openSUSE 13.1 i586/x86-64 with libcxx/libcxxabi enabled:

[ 723s] FAILED: /home/abuild/rpmbuild/BUILD/llvm/stage1/bin/clang++ -DLLVMSupport_EXPORTS -DNDEBUG -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -stdlib=libc++ -fPIC -fvisibility-inlines-hidden -Wall -W -Wno-unused-parameter -Wwrite-strings -Wmissing-field-initializers -pedantic -Wno-long-long -Wcovered-switch-default -Wnon-virtual-dtor -std=c++11 -fcolor-diagnostics -ffunction-sections -fdata-sections -O2 -g -DNDEBUG -fPIC -Ilib/Support -I../lib/Support -Iinclude -I../include -fno-exceptions -MMD -MT lib/Support/CMakeFiles/LLVMSupport.dir/Allocator.cpp.o -MF lib/Support/CMakeFiles/LLVMSupport.dir/Allocator.cpp.o.d -o lib/Support/CMakeFiles/LLVMSupport.dir/Allocator.cpp.o -c ../lib/Support/Allocator.cpp
[ 723s] In file included from ../lib/Support/Allocator.cpp:14:
[ 723s] ../include/llvm/Support/Allocator.h:421:65: error: 'S' does not refer to a value
[ 723s] Size, std::min((size_t)llvm::NextPowerOf2(Size), offsetof(S, x)));
[ 723s] ^
[ 723s] ../include/llvm/Support/Allocator.h:411:10: note: declared here
[ 723s] struct S {
[ 723s] ^
[ 723s] 1 error generated.

The difference between non-working and working preprocessed file is:

@@ -36617,7 +36628,7 @@
} x;
};
return Allocator.Allocate(

•  Size, std::min((size_t)llvm::NextPowerOf2(Size), offsetof(S, x)));
  

•  Size, std::min((size_t)llvm::NextPowerOf2(Size), __builtin_offsetof(S, x)));
  

}

Reverting r207606 fixes the problem.