Move replaceAllUsesWith() from DIType to DIDescriptor.

RAUW was only used on DIType to merge declarations and full definitions
of types. In order to support the same functionality for functions and
global variables, move the function up type DI type hierarchy to the
common parent of DIType, DISubprogram and DIVariable which is
DIDescriptor.

This functionality will be exercized when we add the code to emit
imported declarations for forward declared function/variables.

Reviewers: echristo, dblaikie, aprantl

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5325

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217748 91177308-0d34-0410-b5e6-96231b3b80d8
Fix DebugInfo replaceAllUsesWith.

Summary:
replaceAllUsesWith had been modified to allow a DbgNode value to be
replaced by itself. In that case a new node is created by copying the
current DbgNode and the copy is used as replacement value.

When that copying happens, the value stored in this->DbgNode at the end
of RAUW would be a reference to the Node that has just been deleted.

This doesn't produce any bug right now, because the DI node on which we
call RAUW won't be used again.

Reviewers: dblaikie, echristo, aprantl

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5326

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217749 91177308-0d34-0410-b5e6-96231b3b80d8
InstSimplify: Simplify trivial and/or of icmps

Some ICmpInsts when anded/ored with another ICmpInst trivially reduces
to true or false depending on whether or not all integers or no integers
satisfy the intersected/unioned range.

This sort of trivial looking code can come about when InstCombine
performs a range reduction-type operation on sdiv and the like.

This fixes PR20916.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217750 91177308-0d34-0410-b5e6-96231b3b80d8
Fix ambiguous typedef introduced in r217747.

Use fully qualified name inside a typedef from llvm::iterator_range<...> to
iterator_range. This is reported (rightly I think) by GCC as an
ambiguous name redefinition. Hope this fixes the buildbots.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217751 91177308-0d34-0410-b5e6-96231b3b80d8