[x86] Introduce tests covering the gamut of 256-bit vector shuffling.

These are just test cases, no actual code yet. This establishes the
baseline fallback strategy we're starting from on AVX2 and the expected
lowering we use on AVX1.

Also, these test cases are very much generated. I've manually crafted
the specific pattern set that I'm hoping will be useful at exercising
the lowering code, but I've not (and could not) manually verify *all* of
these. I've spot checked and they seem legit to me.

As with the rest of vector shuffling, at a certain point the only really
useful way to check the correctness of this stuff is through fuzz
testing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218267 91177308-0d34-0410-b5e6-96231b3b80d8
MC: ReadOnlyWithRel section kinds should map to rdata in COFF

Don't consider ReadOnlyWithRel as a writable section in COFF, they
really belong in .rdata.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218268 91177308-0d34-0410-b5e6-96231b3b80d8
ms-inline-asm: Fix parsing label names inside bracket expressions

Summary:
This fixes a couple of issues.  One is ensuring that AOK_Label rewrite
rules have a lower priority than AOK_Skip rules, as AOK_Skip needs to
be able to skip the brackets properly.  The other part of the fix ensures
that we don't overwrite Identifier when looking up the identifier, and
that we use the locally available information to generate the AOK_Label
rewrite in ParseIntelIdentifier.  Doing that in CreateMemForInlineAsm
would be problematic since the Start location there may point to the
beginning of a bracket expression, and not necessarily the beginning of
an identifier.

This also means that we don't need to carry around the InternlName field,
which helps simplify the code.

Test Plan: This will be tested on the clang side.

Reviewers: rnk

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5445

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218270 91177308-0d34-0410-b5e6-96231b3b80d8