[FastISel][AArch64] Move over to target-dependent instruction selection only.

This change moves FastISel for AArch64 to target-dependent instruction selection
only. This change replicates the existing target-independent behavior, therefore
there are no changes to the unit tests or new tests.

Future changes will take advantage of this change and update functionality
and unit tests.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216955 91177308-0d34-0410-b5e6-96231b3b80d8
Add a CFL Alias Analysis implementation

This provides an implementation of CFL alias analysis (including some
supporting data structures). Currently, we don't have any extremely fancy
features, sans some interprocedural analysis (i.e. no field sensitivity, etc.),
and we do best sitting behind BasicAA + TBAA. In such a configuration, we take
~0.6-0.8% of total compile time, and give ~7-8% NoAlias responses to queries
TBAA and BasicAA couldn't answer when bootstrapping LLVM. In testing this on
other projects, we've seen up to 10.5% of queries dropped by BasicAA+TBAA
answered with NoAlias by this algorithm.

Patch by George Burgess IV (with minor modifications by me -- mostly adapting
some BasicAA tests), thanks!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216970 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Relax some ordering in tests.

This will help with enabling misched

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216971 91177308-0d34-0410-b5e6-96231b3b80d8
[asan]  Assign a low branch weight to ASan's slow path, patch by Jonas Wagner. This speeds up asan (at least on SPEC) by 1%-5% or more. Also fix lint in dfsan.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216972 91177308-0d34-0410-b5e6-96231b3b80d8
BumpPtrAllocator: use uintptr_t when aligning addresses to avoid undefined behaviour

In theory, alignPtr() could push a pointer beyond the end of the current slab, making
comparisons with that pointer undefined behaviour. Use an integer type to avoid this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216973 91177308-0d34-0410-b5e6-96231b3b80d8
Add pass-manager flags to use CFL AA

Add -use-cfl-aa (and -use-cfl-aa-in-codegen) to add CFL AA in the default pass
managers (for easy testing).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216978 91177308-0d34-0410-b5e6-96231b3b80d8
[CFLAA] constexpr -> LLVM_CONSTEXPR

Attempt to fix the MSVC build by not using constexpr.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216979 91177308-0d34-0410-b5e6-96231b3b80d8
[X86] Allow atomic operations using immediates to avoid using a register

The only valid lowering of atomic stores in the X86 backend was mov from
register to memory. As a result, storing an immediate required a useless copy
of the immediate in a register. Now these can be compiled as a simple mov.

Similarily, adding/and-ing/or-ing/xor-ing an
immediate to an atomic location (but through an atomic_store/atomic_load,
not a fetch_whatever intrinsic) can now make use of an 'add $imm, x(%rip)'
instead of using a register. And the same applies to inc/dec.

This second point matches the first issue identified in
  http://llvm.org/bugs/show_bug.cgi?id=17281

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216980 91177308-0d34-0410-b5e6-96231b3b80d8