[x86] Minimize the parameters to this test for clarity.

The test has to do with DAG combines, and so it doesn't need the new
vector shuffle lowering to be effective. Also, it has a nice in-IR
triple string which we should really be using rather than command line
flags (unless it varies form RUN-line to RUN-line). Finally, I much
prefer letting LLVM synthesize the correct datalayout string from the
triple rather than baking one in here that will just become stale.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218856 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Update this test to run a full complement of the ISA extensions,
and use the new grouped FileCheck patterns to match them.

No interesting changes yet, but this test is now in proper form to have
the other shuffle combining tests merged into it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218857 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Merge the bitwise operation shuffle combining into the common test
file, adding assertions across the ISA variants for it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218858 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Merge the second set of vector combining tests into a common test
file.

Some of these really don't make sense to test -- we're testing for the
*lack* of combining two shuffles into one, presumably because the two
would generate better shuffles in the end. But if you look at the
generated code shown here, in many cases the generated code is, frankly,
terrible. Or we combine any two generated shuffles back into a single
instruction! I've left a FIXME to revisit these decisions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218859 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Merge the third combining test into the generic one and add proper
checks for all the ISA variants.

If the SSE2 checks here terrify you, good. This is (in large part) the
kind of amazingly bad code that is holding LLVM back when vectorizing on
older ISAs.

At the same time, these tests seem increasingly dubious to me. There are
a very large number of tests and it isn't clear that they are
systematically covering a specific set of functionality. Anyways,
I don't want to reduce testing during the transition, I just want to
consolidate it to where it is easier to manage.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218860 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Merge still more combine tests into the common file. These at
least seem *slightly* more interesting test wise, although given how
spotily we actually combine anything, I remain somewhat suspicious.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218861 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Just delete the last combine test file.

This file isn't really doing anything useful. Many of the tests that
seem to be combined are also repeats from other test files. Many of the
other tests, despite the comment that they should be combined into
a single shuffle... well... aren't combined into a single shuffle.
=/

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218862 91177308-0d34-0410-b5e6-96231b3b80d8