LSR: Compress a pair (and get rid of the DenseMapInfo for it).

Also convert a horrible hash function to use our hashing infrastructure.
No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204008 91177308-0d34-0410-b5e6-96231b3b80d8
PointerIntPair: Avoid an (academic) case of undefined behavior in the DenseMapInfo specialization.

If we use a pair with an enum type this could create values outside
of the enum range. Avoid it by creating the bit pattern directly.
While there turn a dynamic assert into a static one. No functionality
change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204010 91177308-0d34-0410-b5e6-96231b3b80d8
Make some assertions on constant expressions static.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204011 91177308-0d34-0410-b5e6-96231b3b80d8
Remove some dead assignements found by scan-build

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204013 91177308-0d34-0410-b5e6-96231b3b80d8
Use a fixed subtarget for test so atom scheduling can't change the addresses this test relies on.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204014 91177308-0d34-0410-b5e6-96231b3b80d8
Remove named Twine.

While technically correct, we generally disallow any instance of named
Twines due to their subtlety.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204016 91177308-0d34-0410-b5e6-96231b3b80d8