Fix pr19645.

The fix itself is fairly simple: move getAccessVariant to MCValue so that we
replace the old weak expression evaluation with the far more general
EvaluateAsRelocatable.

This then requires that EvaluateAsRelocatable stop when it finds a non
trivial reference kind. And that in turn requires the ELF writer to look
harder for weak references.

Last but not least, this found a case where we were being bug by bug
compatible with gas and accepting an invalid input. I reported pr19647
to track it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207920 91177308-0d34-0410-b5e6-96231b3b80d8
[TBAA] Fix handling of mixed TBAA (path-aware and non-path-aware TBAA).

This fix simply ensures that both metadata nodes are path-aware before
performing path-aware alias analysis.

This issue isn't normally triggered in LLVM, because we perform an autoupgrade
of the TBAA metadata to the new format when reading in LL or BC files. This
issue only appears when a client creates the IR manually and mixes old and new
TBAA metadata format.

This fixes <rdar://problem/16760860>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207923 91177308-0d34-0410-b5e6-96231b3b80d8
IR: Cleanup AttributeSet::get for AttrBuilder

We don't modify the AttrBuilder in AttributeSet::get, make the reference
argument const.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207924 91177308-0d34-0410-b5e6-96231b3b80d8
X86: refactor export directive generation

Create a helper function to generate the export directive.  This was previously
duplicated inline to handle export directives for variables and functions.  This
also enables the use of range-based iterators for the generation of the
directive rather than the traditional loops.  NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207925 91177308-0d34-0410-b5e6-96231b3b80d8
X86: repair export compatibility with MinGW/cygwin

Both MinGW and cygwin (i686) construct export directives without the global
leader prefix.  This is mostly due to the fact that they use GNU ld which does
not correctly handle the export directive.  This apparently has been been broken
for a while.  However, this was recently reported as being broken by
mingwandroid and diorcety of the msys2 project.

Remove the global leader prefix if targeting MinGW or cygwin, otherwise, retain
the global leader prefix.  Add an explicit test for cygwin's behaviour of export
directives.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207926 91177308-0d34-0410-b5e6-96231b3b80d8
X86: remove X86COFFMachineModuleInfo

Remove dead code.  This is vestigial after r98384.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207927 91177308-0d34-0410-b5e6-96231b3b80d8
X86: further range-loopify AsmPrinter

Use more range loops in the X86AsmPrinter.  NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207928 91177308-0d34-0410-b5e6-96231b3b80d8
[LCG] Reorder the tests to be a bit more logical: inter-SCC mutation
before intra-SCC mutation, insertion before removal.

No functionality changed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207934 91177308-0d34-0410-b5e6-96231b3b80d8
[LCG] Add the last (and most complex) of the edge insertion mutation
operations on the call graph. This one forms a cycle, and while not as
complex as removing an internal edge from an SCC, it involves
a reasonable amount of work to find all of the nodes newly connected in
a cycle.

Also somewhat alarming is the worst case complexity here: it might have
to walk roughly the entire SCC inverse DAG to insert a single edge. This
is carefully documented in the API (I hope).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207935 91177308-0d34-0410-b5e6-96231b3b80d8
AVX-512: minor change in rndscale intrinsic


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207937 91177308-0d34-0410-b5e6-96231b3b80d8
SLPVectorizer: Bring back the insertelement patch (r205965) with fixes

When can't assume a vectorized tree is rooted in an instruction. The IRBuilder
could have constant folded it. When we rebuild the build_vector (the series of
InsertElement instructions) use the last original InsertElement instruction. The
vectorized tree root is guaranteed to be before it.

Also, we can't assume that the n-th InsertElement inserts the n-th element into
a vector.

This reverts r207746 which reverted the revert of the revert of r205018 or so.

Fixes the test case in PR19621.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207939 91177308-0d34-0410-b5e6-96231b3b80d8
LoopUnroll: If we're doing partial unrolling, use the PartialThreshold to limit unrolling.

Otherwise we use the same threshold as for complete unrolling, which is
way too high. This made us unroll any loop smaller than 150 instructions
by 8 times, but only if someone specified -march=core2 or better,
which happens to be the default on darwin.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207940 91177308-0d34-0410-b5e6-96231b3b80d8
MC: support FK_SecRel_4 for Windows on ARM

Add handling for FK_SecRel_4 (4-byte section relative relocations).  These are
used by the generation of DWARF debug information (the abbrevations use section
relative relocations).  This will also be used in generation of CodeView line
tables.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207941 91177308-0d34-0410-b5e6-96231b3b80d8
CodeGen: strengthen WoA AEABI avoidance tests

Add additional test cases for WoA AEABI avoidance checking.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207942 91177308-0d34-0410-b5e6-96231b3b80d8
CodeGen: correct memset emittance for WoA

Windows on ARM does not conform to AEABI.  However, memset would be emitted
using the AEABI signature, resulting in inverted parameters.  Handle this
special case appropriately.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207943 91177308-0d34-0410-b5e6-96231b3b80d8