I'll admit I'm not entirely satisfied with this change, but it seemed
the cleanest option. Other suggestions quite welcome

The issue is that the traits specializations have static methods which
return the typedef'ed PHI_iterator type. In both the IR and MI layers
this is typedef'ed to a custom iterator class defined in an anonymous
namespace giving the types and the functions returning them internal
linkage. However, because the traits specialization is defined in the
'llvm' namespace (where it has to be, specialized template lives there),
and is in turn used in the templated implementation of the SSAUpdater.
This led to the linkage conflict that Clang now warns about.

The simplest solution to me was just to define the PHI_iterator as
a nested class inside the trait specialization. That way it still
doesn't get scoped widely, it can't be accidentally reused somewhere,
etc. This is a little gross just because nested class definitions are
a little gross, but the alternatives seem more ad-hoc.

llvm-svn: 158799

llvm-svn: 148578

llvm-svn: 145903

SSAUpdater for the value from the first def may see uses of undefined values,
because the later defs will not have been updated yet.

llvm-svn: 103407

MachineSSAUpdater to avoid duplicating all the code.

llvm-svn: 103060

SSAUpdater.  I'm going to try to refactor this to share most of the code
between them.

llvm-svn: 102353

llvm-svn: 100215

llvm-svn: 95745

into TargetOpcodes.h.  #include the new TargetOpcodes.h
into MachineInstr.  Add new inline accessors (like isPHI())
to MachineInstr, and start using them throughout the 
codebase.

llvm-svn: 95687

Change errs() to dbgs().

llvm-svn: 92548

llvm-svn: 90816

llvm-svn: 90759

llvm-svn: 90744

llvm-svn: 90566

- If the reaching definition is an undef and the use is a PHI, add the implicit_def to the end of the source block.
- When reaching value is replaced with another, update the cache as well.

llvm-svn: 90501

llvm-svn: 90489

llvm-svn: 90395

llvm-svn: 90353