Remove a DenseMapInfo specialization for std::pair -- we have one of
those baked into DenseMap now.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186773 91177308-0d34-0410-b5e6-96231b3b80d8
Comment: try to clarify loop iteration order.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186774 91177308-0d34-0410-b5e6-96231b3b80d8
Reformat the implementation of mem2reg with clang-format so that my
subsequent changes don't introduce inconsistencies.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186775 91177308-0d34-0410-b5e6-96231b3b80d8
Rename constructor parameters to follow the common member-shadowing
pattern and conform to the naming conventions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186776 91177308-0d34-0410-b5e6-96231b3b80d8
Don't allocate the DIBuilder on the heap and remove all the complexity
that ensued from that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186777 91177308-0d34-0410-b5e6-96231b3b80d8
Don't crash when llvm.compiler.used becomes empty.

GlobalOpt simplifies llvm.compiler.used by removing any members that are also
in the more strict llvm.used. Handle the special case where llvm.compiler.used
becomes empty.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186778 91177308-0d34-0410-b5e6-96231b3b80d8
Sink a typedef and comparator down to the function that actually uses them.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186779 91177308-0d34-0410-b5e6-96231b3b80d8
Hoist the AllocaInfo struct to the top of the file.

This struct is nicely independent of everything else, and we already
needed a foward declaration here. It's simpler to just define it
immediately.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186780 91177308-0d34-0410-b5e6-96231b3b80d8