Add _Float128 as alias to __float128 to enable compilations on Fedora27/glibc2-26

Fedora27 is using a new version of glibc that refers to the _Float128 type. This
patch adds that name as an alias to float128. I also added some predefined macro
values for the digits, mantissa, epilon, etc (FloatMacros). For the test case, I
copied an existing float128 test. This functionality needs work long term, but 
it should be sufficient to tread water for a while. At Intel we have test
servers running our LLVM compiler with various open source workloads, the server
has been upgraded to Fedora27 so many workloads are failing due to _Float128.

Patch-By: mibintc
Differential Revision: https://reviews.llvm.org/D40673

llvm-svn: 319703
4 files changed
tree: 6be9b26c316f19790d543abccf99632b0c9471bf
  1. clang/
  2. clang-tools-extra/
  3. compiler-rt/
  4. debuginfo-tests/
  5. libclc/
  6. libcxx/
  7. libcxxabi/
  8. libunwind/
  9. lld/
  10. lldb/
  11. llgo/
  12. llvm/
  13. openmp/
  14. parallel-libs/
  15. polly/
  16. README.md
README.md

Low Level Virtual Machine (LLVM)

This directory and its subdirectories contain source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and runtime environments.