Add LLVM_ATTRIBUTE_UNUSED to function currently just used in an assert

Fixes break when -Wunused-function is used.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219833 91177308-0d34-0410-b5e6-96231b3b80d8
Teach ScalarEvolution to sharpen range information.
    
If x is known to have the range [a, b) in a loop predicated by (icmp
ne x, a), its range can be sharpened to [a + 1, b).  Get
ScalarEvolution and hence IndVars to exploit this fact.
    
This change triggers an optimization to widen-loop-comp.ll, so it had
to be edited to get it to pass.

phabricator: http://reviews.llvm.org/D5639



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219834 91177308-0d34-0410-b5e6-96231b3b80d8
Allow forward references to section symbols.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219835 91177308-0d34-0410-b5e6-96231b3b80d8
Wrong attribute. LLVM_ATTRIBUTE_USED not LLVM_ATTRIBUTE_UNUSED

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219837 91177308-0d34-0410-b5e6-96231b3b80d8