GlobalOpt: Preserve comdats of unoptimized initializers

Rather than slurping in and splatting out the whole ctor list, preserve
the existing array entries without trying to understand them.  Only
remove the entries that we know we can optimize away.  This way we don't
need to wire through priority and comdats or anything else we might add.

Fixes a linker issue where the .init_array or .ctors entry would point
to discarded initialization code if the comdat group from the TU with
the faulty global_ctors entry was dropped.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218337 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Teach the new vector shuffle lowering to lower v4i64 vector
shuffles using the AVX2 instructions. This is the first step of cutting
in real AVX2 support.

Note that I have spotted at least one bug in the test cases already, but
I suspect it was already present and just is getting surfaced. Will
investigate next.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218338 91177308-0d34-0410-b5e6-96231b3b80d8
Fix swift-atomics testcase

This testcase was not testing what it meant: because there were only two checks for
dmb {{ish}} in the second function, it could have missed a bug where one of the three
required dmb {{ish}} became dmb {{ishst}}. As I was fixing it, I also added
CHECK-LABELs to make it a bit less brittle.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218341 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Fix a really terrible bug in the repeated 128-bin-lane shuffle
detection. It was incorrectly handling undef lanes by actually treating
an undef lane in the first 128-bit lane as a *numeric* shuffle value.

Fortunately, this almost always DTRT and disabled detecting repeated
patterns. But not always. =/ This patch introduces a much more
principled approach and fixes the miscompiles I spotted by inspection
previously.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218346 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Teach the new vector shuffle lowering to lower v8i32 shuffles with
the native AVX2 instructions.

Note that the test case is really frustrating here because VPERMD
requires the mask to be in the register input and we don't produce
a comment looking through that to the constant pool. I'm going to
attempt to improve this in a subsequent commit, but not sure if I will
succeed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218347 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Implement VGPR register spilling for compute at -O0 v3

VGPRs are spilled to LDS.  This still needs more testing, but
we need to at least enable it at -O0, because the fast register
allocator spills all registers that are live at the end of blocks
and without this some future commits will break the
flat-address-space.ll test.

v2: Only calculate thread id once

v3: Move insertion of spill instructions to
    SIRegisterInfo::eliminateFrameIndex()

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218348 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Fix SIRegisterInfo::getPhysRegSubReg()

Correctly handle special registers: EXEC, EXEC_LO, EXEC_HI, VCC_LO,
VCC_HI, and M0.  The previous implementation would assertion fail
when passed these registers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218349 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Mark EXEC_LO and EXEC_HI as reserved

These registers can be allocated and used like other 32-bit registers,
but it seems like a likely source for bugs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218350 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Fix the FixSGPRLiveRanges pass

The previous implementation was extending the live range of SGPRs
by modifying the live intervals directly.  This was causing a lot
of machine verification errors when the machine scheduler was enabled.

The new implementation adds pseudo instructions with implicit uses to
extend the live ranges of SGPRs, which works much better.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218351 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Move PHIs that define SGPRs to the VALU in most cases

This fixes a bug that is uncovered by a future commit and will
be tested by the test/CodeGen/R600/sgpr-control-flow.ll test case.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218352 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Enable selecting SALU inside branches

We can do this now that the FixSGPRLiveRanges pass is working.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218353 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Fix weird CHECK-DAG usage

This prevents these from failing in a future commit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218356 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Start refactoring the comment printing logic in the MC lowering of
vector shuffles.

This is just the beginning by hoisting it into its own function and
making use of early exit to dramatically simplify the flow of the
function. I'm going to be incrementally refactoring this until it is
a bit less magical how this applies to other instructions, and I can
teach it how to dig a shuffle mask out of a register. Then I plan to
hook it up to VPERMD so we get our mask comments for it.

No functionality changed yet.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218357 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Enable named operand table for SALU instructions

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218358 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Fix hardcoded and wrong operand numbers.

Also fix leftover debug printing

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218359 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Add new helper isSGPRClassID

Move these into header since they are trivial

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218360 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Hoist the logic for extracting the relevant bits of information
from the MachineInstr into the caller which is already doing a switch
over the instruction.

This will make it more clear how to compute different operands to feed
the comment selection for example.

Also, in a drive-by-fix, don't append an empty comment string (which is
a no-op ultimately).

No functionality changed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218361 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Bypass the shuffle mask comment generation when not using verbose
asm. This can be somewhat expensive and there is no reason to do it
outside of tests or debugging sessions. I'm also likely to make it
significantly more expensive to support more styles of shuffles.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218362 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] More refactoring of the shuffle comment emission. The previous
attempt didn't work out so well. It looks like it will be much better
for introducing extra logic to find a shuffle mask if the finding logic
is totally separate. This also makes it easy to sink the opcode logic
completely out of the routine so we don't re-dispatch across it.

Still no functionality changed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218363 91177308-0d34-0410-b5e6-96231b3b80d8
Clear PreferredExtendType for in each function-specific state FunctionLoweringInfo.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218364 91177308-0d34-0410-b5e6-96231b3b80d8