[FastISel][AArch64] Don't fold the 'and' instruction into the 'tbz/tbnz' instruction if it is in a different basic block.

This fixes a bug where the input register was not defined for the 'tbz/tbnz'
instruction. This happened, because we folded the 'and' instruction from a
different basic block.

This fixes rdar://problem/18784013.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220704 91177308-0d34-0410-b5e6-96231b3b80d8
[FastISel][AArch64] Use 'cbz' also for null values (pointers).

The pattern matching for a 'ConstantInt' value was too restrictive. Checking for
a 'Constant' with a bull value is sufficient for using an 'cbz/cbnz' instruction.

This fixes rdar://problem/18784732.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220709 91177308-0d34-0410-b5e6-96231b3b80d8
Stackmap shadows should consider call returns a branch target.

To avoid emitting too many nops, a stackmap shadow can include emitted instructions in the shadow, but these must not include branch targets.

A return from a call should count as a branch target as patching over the instructions after the call would lead to incorrect behaviour for threads currently making that call, when they return.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220710 91177308-0d34-0410-b5e6-96231b3b80d8
[FastISel][AArch64] Optimize compare-and-branch for i1 to use 'tbz'.

Minor enhancement to use 'tbz' for i1 compare-and-branch to get rid of an 'and'
instruction.

This fixes rdar://problem/18784953.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220712 91177308-0d34-0410-b5e6-96231b3b80d8
[FastISel][AArch64] Emit immediate version of icmp (subs) for null pointer check.

This is a minor change to use the immediate version when the operand is a null
value. This should get rid of an unnecessary 'mov' instruction in debug
builds and align the code more with the one generated by SelectionDAG.

This fixes rdar://problem/18785125.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220713 91177308-0d34-0410-b5e6-96231b3b80d8