Support using sample profiles with partial debug info.

Summary:
When using a profile, we used to require the use -gmlt so that we could
get access to the line locations. This is used to match line numbers in
the input profile to the line numbers in the function's IR.

But this is actually not necessary. The driver can provide source
location tracking without the emission of debug information. In these
cases, the annotation 'llvm.dbg.cu' is missing from the IR, but the
actual line location annotations are still present.

This patch adds a new way of looking for the start of the current
function. Instead of looking through the compile units in llvm.dbg.cu,
we can walk up the scope for the first instruction in the function with
a debug loc. If that describes the function, we use it. Otherwise, we
keep looking until we find one.

If no such instruction is found, we then give up and produce an error.

Reviewers: echristo, dblaikie

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5887

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220382 91177308-0d34-0410-b5e6-96231b3b80d8
Fixing a -Wsign-compare warning; NFC.

I think it might make sense to make COFF::MaxNumberOfSections16 be a uint32_t, however, that may have wider-reaching implications in other projects, which is why I did not change that declaration.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220384 91177308-0d34-0410-b5e6-96231b3b80d8
[PowerPC] Support select-cc for VSX

The tests test/CodeGen/Generic/select-cc.ll and
test/CodeGen/PowerPC/select-cc.ll both fail with VSX enabled.  The
problem is that the lowering logic for the SELECT and SELECT_CC
operations doesn't currently support the VSX registers.  This patch
fixes that.

In lib/Target/PowerPC/PPCInstrInfo.td, we have pseudos to handle this
for other register classes.  Similar pseudos are added in
PPCInstrVSX.td (they must be there, because the "vsrc" register class
definition appears there) for the VSRC register class.  The
SELECT_VSRC pseudo is then used in pattern matching for SELECT_CC.

The rest of the patch just adds logic for SELECT_VSRC wherever similar
logic appears for SELECT_VRRC.

There are no new test cases because the existing tests above test
this, along with a variant in test/CodeGen/PowerPC/vsx.ll.

After discussion with Hal, a future patch will add similar _VSFRC
variants to override f64 type handling (currently using F8RC).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220385 91177308-0d34-0410-b5e6-96231b3b80d8
Change error to warning when a profile cannot be found.

When the profile for a function cannot be applied, we use to emit an
error. This seems extreme. The compiler can continue, it's just that the
optimization opportunities won't include profile information.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220386 91177308-0d34-0410-b5e6-96231b3b80d8