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[X86][AVX] Remove superfluous insert_subvector(zero, bitcast(x)) -> bitcast(insert_subvector(zero, x)) fold 

This is caught by other existing bitcast folds.

llvm-svn: 355084
This commit is contained in:
Simon Pilgrim 2019-02-28 11:39:52 +00:00
parent cf0ff638bc
commit 134bc19079
1 changed files with 0 additions and 14 deletions
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14
llvm/lib/Target/X86/X86ISelLowering.cpp
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@ -41888,20 +41888,6 @@ static SDValue combineInsertSubvector(SDNode *N, SelectionDAG &DAG,
getZeroVector(OpVT, Subtarget, DAG, dl), getZeroVector(OpVT, Subtarget, DAG, dl),
Ins.getOperand(1), N->getOperand(2)); Ins.getOperand(1), N->getOperand(2));
} }
// If we're inserting a bitcast into zeros, rewrite the insert and move the
// bitcast to the other side. This helps with detecting zero extending
// during isel.
// TODO: Is this useful for other indices than 0?
if (!IsI1Vector && SubVec.getOpcode() == ISD::BITCAST && IdxVal == 0) {
MVT CastVT = SubVec.getOperand(0).getSimpleValueType();
unsigned NumElems = OpVT.getSizeInBits() / CastVT.getScalarSizeInBits();
MVT NewVT = MVT::getVectorVT(CastVT.getVectorElementType(), NumElems);
SDValue Insert = DAG.getNode(ISD::INSERT_SUBVECTOR, dl, NewVT,
DAG.getBitcast(NewVT, Vec),
SubVec.getOperand(0), N->getOperand(2));
return DAG.getBitcast(OpVT, Insert);
}
} }
// Stop here if this is an i1 vector. // Stop here if this is an i1 vector.