Move the complex address expression out of DIVariable and into an extra
argument of the llvm.dbg.declare/llvm.dbg.value intrinsics.

Previously, DIVariable was a variable-length field that has an optional
reference to a Metadata array consisting of a variable number of
complex address expressions. In the case of OpPiece expressions this is
wasting a lot of storage in IR, because when an aggregate type is, e.g.,
SROA'd into all of its n individual members, the IR will contain n copies
of the DIVariable, all alike, only differing in the complex address
reference at the end.

By making the complex address into an extra argument of the
dbg.value/dbg.declare intrinsics, all of the pieces can reference the
same variable and the complex address expressions can be uniqued across
the CU, too.
Down the road, this will allow us to move other flags, such as
"indirection" out of the DIVariable, too.

The new intrinsics look like this:
declare void @llvm.dbg.declare(metadata %storage, metadata %var, metadata %expr)
declare void @llvm.dbg.value(metadata %storage, i64 %offset, metadata %var, metadata %expr)

This patch adds a new LLVM-local tag to DIExpressions, so we can detect
and pretty-print DIExpression metadata nodes.

What this patch doesn't do:

This patch does not touch the "Indirect" field in DIVariable; but moving
that into the expression would be a natural next step.

http://reviews.llvm.org/D4919
rdar://problem/17994491

Thanks to dblaikie and dexonsmith for reviewing this patch!

Note: I accidentally committed a bogus older version of this patch previously.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218787 91177308-0d34-0410-b5e6-96231b3b80d8
ARM: allow copying of CPSR when all else fails.

As with x86 and AArch64, certain situations can arise where we need to spill
CPSR in the middle of a calculation. These should be avoided where possible
(MRS/MSR is rather expensive), which ARM is actually better at than the other
two since it tries to Glue defs to uses, but as a last ditch effort, copying is
better than crashing.

rdar://problem/18011155

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218789 91177308-0d34-0410-b5e6-96231b3b80d8
[X86 disasm tblegen backend] Clean up numPhysicalOperands asserts

No functionality change intended.

This implements Elena's idea to put the new additionalOperand outside the
switch to cover all cases
(http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20140929/237763.html).

Note only nontrivial change is in MRMSrcMemFrm.  This requires an inclusive
interval of [2, 4] because we have prefix-dependent *optional* immediate
operand.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218790 91177308-0d34-0410-b5e6-96231b3b80d8
Don't repeat function/variable name in comment. NFC.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218791 91177308-0d34-0410-b5e6-96231b3b80d8