Andrea Di Biagio 6ec3395335 [X86] Teach the backend how to fold target specific dag node for packed
vector shift by immedate count (VSHLI/VSRLI/VSRAI) into a build_vector when
the vector in input to the shift is a build_vector of all constants or UNDEFs.

Target specific nodes for packed shifts by immediate count are in
general introduced by function 'getTargetVShiftByConstNode' (in
X86ISelLowering.cpp) when lowering shift operations, SSE/AVX immediate
shift intrinsics and (only in very few cases) SIGN_EXTEND_INREG dag
nodes.

This patch adds extra rules for simplifying vector shifts inside
function 'getTargetVShiftByConstNode'.

Added file test/CodeGen/X86/vec_shift5.ll to verify that packed
shifts by immediate are correctly folded into a build_vector when the
input vector to the shift dag node is a vector of constants or undefs.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198113 91177308-0d34-0410-b5e6-96231b3b80d8
2013-12-28 11:11:52 +00:00
2013-12-20 00:33:39 +00:00
2013-12-04 09:42:49 +00:00
2013-11-20 10:10:50 +00:00
2013-12-20 00:33:39 +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
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started with LLVM and docs/README.txt for an overview of LLVM's
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If you're writing a package for LLVM, see docs/Packaging.rst for our
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LLVM backend for 6502
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