diff options
| author | Chris Lattner <sabre@nondot.org> | 2006-03-28 22:19:47 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2006-03-28 22:19:47 +0000 |
| commit | cef896e50cf58e6b3dc3cd431693d78b8ebfa079 (patch) | |
| tree | 78ed2608cdcd268e8685219938444e5ce05453bc /lib/CodeGen/SelectionDAG/DAGCombiner.cpp | |
| parent | 66445d3e0a3c6d02585a3c18ec295451a80d427c (diff) | |
When building a VVECTOR_SHUFFLE node from extract_element operations, make
sure to build it as SHUFFLE(X, undef, mask), not SHUFFLE(X, X, mask).
The later is not canonical form, and prevents the PPC splat pattern from
matching. For a particular splat, we go from generating this:
li r10, lo16(LCPI1_0)
lis r11, ha16(LCPI1_0)
lvx v3, r11, r10
vperm v3, v2, v2, v3
to generating:
vspltw v3, v2, 3
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@27236 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/SelectionDAG/DAGCombiner.cpp')
| -rw-r--r-- | lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 1c90f78435..a559d3e469 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -2419,7 +2419,17 @@ SDOperand DAGCombiner::visitVBUILD_VECTOR(SDNode *N) { // Return the new VVECTOR_SHUFFLE node. std::vector<SDOperand> Ops; Ops.push_back(VecIn1); - Ops.push_back(VecIn2.Val ? VecIn2 : VecIn1); // Use V1 twice if no V2. + if (VecIn2.Val) { + Ops.push_back(VecIn2); + } else { + // Use an undef vbuild_vector as input for the second operand. + std::vector<SDOperand> UnOps(NumInScalars, + DAG.getNode(ISD::UNDEF, + cast<VTSDNode>(EltType)->getVT())); + UnOps.push_back(NumElts); + UnOps.push_back(EltType); + Ops.push_back(DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, UnOps)); + } Ops.push_back(DAG.getNode(ISD::VBUILD_VECTOR,MVT::Vector, BuildVecIndices)); Ops.push_back(NumElts); Ops.push_back(EltType); |