Bug#919628: Apply Julia's LLVM patches

[Mo Zhou]

Hi Sylvestre,

Please cherry-pick at least: (8) (12) (13) (14) (15)

Recommended to include: (1) (2) (4) (5) (11)

Feel free to ignore: (6) (9) (16) (17)

I have no idea about: (3) (7) (10)

https://github.com/JuliaLang/julia/tree/master/deps/patches
I've listed patches for llvm 6.0.1

========================================================


(1) [unwind] llvm-D27629-AArch64-large_model_6.0.1

    Fix unwind info relocation with large code model on AArch64
    https://reviews.llvm.org/D27629

(2) [performance] llvm-D34078-vectorize-fdiv

    Enable support for floating-point division reductions
    https://reviews.llvm.org/D34078

(3) [nvptx] llvm-6.0-NVPTX-addrspaces

    No idea about this patch.

(4) [performance regression] llvm-D42262-jumpthreading-not-i1

    For details see Julia commit: e94a1f8b08e0bc3b8093d8f1dc2bf3c8f5d59519
    merged upstream: https://reviews.llvm.org/D42262

(5) [???] llvm-PPC-addrspaces

    merged upstream: https://reviews.llvm.org/D43781

(6) [ignore: mingw] llvm-6.0.0_D27296-libssp
    [ignore: mingw] llvm-6.0-D44650

(7) [???] llvm-D46460

    still under review: https://reviews.llvm.org/D46460

(8) [???] llvm-rL327898

    https://github.com/JuliaLang/julia/blob/master/deps/patches/llvm-rL327898.patch
    Fixes Julia issues: #27055 #27080 #27032 #27603

(9) [ignore: compiler complain] llvm-6.0-DISABLE_ABI_CHECKS

(10) [profiling] llvm-OProfile-line-num

(11) [profiling] llvm-D44892-Perf-integration

     merged upstream: https://reviews.llvm.org/D44892

(12) [bug fix] llvm-D49832-SCEVPred
     [bug fix] llvm-rL323946-LSRTy

    Add LLVM patches for bugs introducing illegal ptrtoint
    rL323946 [LSR] Don't force bases of foldable formulae to the final type.
    D49832   [SCEV] Don't expand Wrap predicate using inttoptr in ni addrspaces

(13) llvm-D50010-VNCoercion-ni

    Fixes julia issue: #28360 (#28362)
    https://reviews.llvm.org/D50010

(14) llvm-D50167-scev-umin

    Add LLVM patch to explicitly represent umin in SCEV (#28403)
    Fix mix-type arithmetic detection in umin/max expansion (#28465)
    Fixes #28464
    Fixes #28379
    Fixes #28388

(15) llvm-rL326967-aligned-load

    Fixes incorrect codegen: #28726

(16) [ignore: win64] llvm-D51842-win64-byval-cc

(17) [...] llvm-D57118-powerpc

    https://reviews.llvm.org/D57118