Revert r75610 (and r75620, which was blocking the revert), in the hopes of

Revert r75610 (and r75620, which was blocking the revert), in the hopes of
unbreaking llvm-gcc (on Darwin).

--- Reverse-merging r75620 into '.':
U    include/llvm/Support/Mangler.h
--- Reverse-merging r75610 into '.':
U    test/CodeGen/X86/loop-hoist.ll
G    include/llvm/Support/Mangler.h
U    lib/Target/X86/AsmPrinter/X86ATTAsmPrinter.cpp
U    lib/VMCore/Mangler.cpp

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75636 91177308-0d34-0410-b5e6-96231b3b80d8