[FastISel][AArch64] Update function and variable names to follow the coding standard. NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217845 91177308-0d34-0410-b5e6-96231b3b80d8
[FastISel][AArch64] Allow handling of vectors during return lowering for little endian machines.

Allow handling of vectors during return lowering at least for little endian machines.
This was restricted in r208200 to fix it for big endian machines (according to
the comment), but it also disabled it for little endian too.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217846 91177308-0d34-0410-b5e6-96231b3b80d8
[FastISel][AArch64] Add missing test case for previous commit.

This adds the missing test case for the previous commit:
Allow handling of vectors during return lowering for little endian machines.

Sorry for the noise.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217847 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Add the beginnings of a proper DAG combine to match ADDSUBPS and
ADDSUBPD nodes out of blends of adds and subs.

This allows us to actually form these instructions with SSE3 rather than
only forming them when we had both SSE3 for the ADDSUB instructions and
SSE4.1 for the blend instructions. ;] Kind-of important.

I've adjusted the CPU requirements on one of the tests to demonstrate
this kicking in nicely for an SSE3 cpu configuration.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217848 91177308-0d34-0410-b5e6-96231b3b80d8