Hal Finkel 65fafbb109 Look at shuffles of build_vectors in DAGCombiner::visitEXTRACT_VECTOR_ELT ...

When the loop vectorizer vectorizes code that uses the loop induction variable,
we often end up with IR like this:

  %b1 = insertelement <2 x i32> undef, i32 %v, i32 0
  %b2 = shufflevector <2 x i32> %b1, <2 x i32> undef, <2 x i32> zeroinitializer
  %i = add <2 x i32> %b2, <i32 2, i32 3>

If the add in this example is not legal (as is the case on PPC with VSX), it
will be scalarized, and we'll end up with a number of extract_vector_elt nodes
with the vector shuffle as the input operand, and that vector shuffle is fed by
one or more build_vector nodes. By the time that vector operations are
expanded, visitEXTRACT_VECTOR_ELT will not create new extract_vector_elt by
looking through the vector shuffle (to make sure that no illegal operations are
created), and so the extract_vector_elt -> vector shuffle -> build_vector is
never simplified to an operand of the build vector.

By looking at build_vectors through a shuffle we fix this particular situation,
preventing a vector from being built, only to be deconstructed again (for the
scalarized add) -- an expensive proposition when this all needs to be done via
the stack. We probably want a more comprehensive fix here where we look back
recursively through any shuffles to any build_vectors or scalar_to_vectors,
etc. but that can come later.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205179 91177308-0d34-0410-b5e6-96231b3b80d8

2014-03-31 11:43:19 +00:00

..

CMakeLists.txt

llvm/lib: [CMake] Add explicit dependency to intrinsics_gen.

2012-06-24 13:32:01 +00:00

DAGCombiner.cpp

Look at shuffles of build_vectors in DAGCombiner::visitEXTRACT_VECTOR_ELT

2014-03-31 11:43:19 +00:00

FastISel.cpp

Phase 2 of the great MachineRegisterInfo cleanup. This time, we're changing

2014-03-13 23:12:04 +00:00

FunctionLoweringInfo.cpp

[C++11] Add range based accessors for the Use-Def chain of a Value.

2014-03-09 03:16:01 +00:00

InstrEmitter.cpp

Make stackmap machineinstrs clobber the scratch regs too.

2014-03-05 07:08:16 +00:00

InstrEmitter.h

Revert "Give internal classes hidden visibility."

2013-09-11 18:05:11 +00:00

LegalizeDAG.cpp

Make use of previously generated stores in SelectionDAGLegalize::ExpandExtractFromVectorThroughStack

2014-03-30 15:10:18 +00:00

LegalizeFloatTypes.cpp

Keep TBAA info when rewriting SelectionDAG loads and stores

2013-10-28 11:17:59 +00:00

LegalizeIntegerTypes.cpp

IR: add a second ordering operand to cmpxhg for failure

2014-03-11 10:48:52 +00:00

LegalizeTypes.cpp

[C++11] Add 'override' keyword to virtual methods that override their base class.

2014-03-08 06:31:39 +00:00

LegalizeTypes.h

[AArch64 NEON] Fix pattern match failed on FP_ROUND from v1f128 to v1f64.

2014-01-26 02:19:35 +00:00

LegalizeTypesGeneric.cpp

[C++11] Replace llvm::tie with std::tie.

2014-03-02 13:30:33 +00:00

LegalizeVectorOps.cpp

[VectorLegalizer/X86] Don't unvectorize fp_to_uint for v8f32->v8i16

2014-03-17 17:06:14 +00:00

LegalizeVectorTypes.cpp

Add support for scalarizing/splitting vector bswap.

2014-03-18 17:49:12 +00:00

LLVMBuild.txt

…

Makefile

…

ResourcePriorityQueue.cpp

[C++11] Replace llvm::next and llvm::prior with std::next and std::prev.

2014-03-02 12:27:27 +00:00

ScheduleDAGFast.cpp

[C++11] Add 'override' keyword to virtual methods that override their base class.

2014-03-08 06:31:39 +00:00

ScheduleDAGRRList.cpp

Remove copy ctors that did the same thing as the default one.

2014-03-11 11:32:49 +00:00

ScheduleDAGSDNodes.cpp

[C++11] Replace llvm::next and llvm::prior with std::next and std::prev.

2014-03-02 12:27:27 +00:00

ScheduleDAGSDNodes.h

[C++11] Add 'override' keyword to virtual methods that override their base class.

2014-03-08 06:31:39 +00:00

ScheduleDAGVLIW.cpp

[C++11] Add 'override' keyword to virtual methods that override their base class.

2014-03-08 06:31:39 +00:00

SDNodeDbgValue.h

[Layering] Move DebugLoc.h into the IR library. The implementation

2014-03-05 10:30:38 +00:00

SelectionDAG.cpp

Prevent alias from pointing to weak aliases.

2014-03-27 15:26:56 +00:00

SelectionDAGBuilder.cpp

Avoid storing Twines.

2014-03-29 16:54:29 +00:00

SelectionDAGBuilder.h

Replace '#include ValueTypes.h' with forward declarations.

2014-03-12 08:00:24 +00:00

SelectionDAGDumper.cpp

[Layering] Move DebugInfo.h into the IR library where its implementation

2014-03-06 00:46:21 +00:00

SelectionDAGISel.cpp

Phase 1 of refactoring the MachineRegisterInfo iterators to make them suitable

2014-03-13 06:02:25 +00:00

SelectionDAGPrinter.cpp

[Layering] Move DebugInfo.h into the IR library where its implementation

2014-03-06 00:46:21 +00:00

TargetLowering.cpp

Fix creating illegal setcc cond codes.

2014-03-25 16:09:21 +00:00

TargetSelectionDAGInfo.cpp

Rename some member variables from TD to DL.

2014-02-18 15:33:12 +00:00