Changes in directory llvm/lib/CodeGen/SelectionDAG:
DAGCombiner.cpp updated: 1.132 -> 1.133
---
Log message:
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
---
Diffs of the changes: (+11 -1)
DAGCombiner.cpp | 12 +++++++++++-
1 files changed, 11 insertions(+), 1 deletion(-)
Index: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
diff -u llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1.132
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1.133
--- llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1.132 Tue Mar 28 16:11:53 2006
+++ llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Tue Mar 28 16:19:47 2006
@@ -2419,7 +2419,17 @@
// 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);
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