[mips][msa] Non-constant BUILD_VECTOR's should be expanded to INSERT_VECTOR_ELT instead of memory operations.
The resulting code is the same length, but doesnt cause memory traffic or latency.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191297 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Mips/MipsSEISelLowering.cpp b/lib/Target/Mips/MipsSEISelLowering.cpp
index 3077454..1575cde 100644
--- a/lib/Target/Mips/MipsSEISelLowering.cpp
+++ b/lib/Target/Mips/MipsSEISelLowering.cpp
@@ -1668,6 +1668,23 @@
}
else if (isSplatVector(Node))
return DAG.getNode(MipsISD::VSPLAT, DL, ResTy, Op->getOperand(0));
+ else {
+ // Use INSERT_VECTOR_ELT operations rather than expand to stores.
+ // The resulting code is the same length as the expansion, but it doesn't
+ // use memory operations
+ EVT ResTy = Node->getValueType(0);
+
+ assert(ResTy.isVector());
+
+ unsigned NumElts = ResTy.getVectorNumElements();
+ SDValue Vector = DAG.getUNDEF(ResTy);
+ for (unsigned i = 0; i < NumElts; ++i) {
+ Vector = DAG.getNode(ISD::INSERT_VECTOR_ELT, DL, ResTy, Vector,
+ Node->getOperand(i),
+ DAG.getConstant(i, MVT::i32));
+ }
+ return Vector;
+ }
return SDValue();
}