Chandler Carruth a644b090de [x86] Teach the new vector shuffle lowering how to lower 128-bit
shuffles using AVX and AVX2 instructions. This fixes PR21138, one of the
few remaining regressions impacting benchmarks from the new vector
shuffle lowering.

You may note that it "regresses" many of the vperm2x128 test cases --
these were actually "improved" by the naive lowering that the new
shuffle lowering previously did. This regression gave me fits. I had
this patch ready-to-go about an hour after flipping the switch but
wasn't sure how to have the best of both worlds here and thought the
correct solution might be a completely different approach to lowering
these vector shuffles.

I'm now convinced this is the correct lowering and the missed
optimizations shown in vperm2x128 are actually due to missing
target-independent DAG combines. I've even written most of the needed
DAG combine and will submit it shortly, but this part is ready and
should help some real-world benchmarks out.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219079 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-05 11:41:36 +00:00
2014-09-02 22:28:02 +00:00
2014-10-04 15:44:01 +00:00

Low Level Virtual Machine (LLVM)
================================

This directory and its subdirectories contain source code for the Low Level
Virtual Machine, a toolkit for the construction of highly optimized compilers,
optimizers, and runtime environments.

LLVM is open source software. You may freely distribute it under the terms of
the license agreement found in LICENSE.txt.

Please see the documentation provided in docs/ for further
assistance with LLVM, and in particular docs/GettingStarted.rst for getting
started with LLVM and docs/README.txt for an overview of LLVM's
documentation setup.

If you're writing a package for LLVM, see docs/Packaging.rst for our
suggestions.
Description
LLVM backend for 6502
Readme 277 MiB
Languages
C++ 48.7%
LLVM 38.5%
Assembly 10.2%
C 0.9%
Python 0.4%
Other 1.2%