Revert "Remove isCastable since nothing uses it now"

Apparently dragonegg uses it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187454 91177308-0d34-0410-b5e6-96231b3b80d8
Respect address space sizes in isEliminableCastPair.

This avoids constant folding bitcast/ptrtoint/inttoptr combinations
that have illegal bitcasts between differently sized address spaces.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187455 91177308-0d34-0410-b5e6-96231b3b80d8
Make sure that -gsplit-dwarf isn't passed to the linker.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187456 91177308-0d34-0410-b5e6-96231b3b80d8
Make these just inline, not static inline.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187457 91177308-0d34-0410-b5e6-96231b3b80d8
Reflow this to be easier to read.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187459 91177308-0d34-0410-b5e6-96231b3b80d8