Allow targets to specify their choice of calling conventions per
libcall. Take advantage of this in the ARM backend to rectify broken
choice of CC when hard float is in effect. PIC16 may want to see if
it could be of use in MakePIC16Libcall, which works unchanged.

Patch by Sandeep!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79033 91177308-0d34-0410-b5e6-96231b3b80d8
7 files changed