[Power PC] softening long double type

This patch implements softening of long double type (ppcf128) on ppc32
architecture and enables operations for this type for soft float.

Patch by Strahinja Petrovic.

Differential Revision: http://reviews.llvm.org/D15811


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259791 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed