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-rw-r--r--llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp4
-rw-r--r--llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp4
2 files changed, 8 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index fb64fa3667f..dad94c58ce9 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -5217,7 +5217,11 @@ SDValue DAGCombiner::visitBSWAP(SDNode *N) {
SDValue DAGCombiner::visitBITREVERSE(SDNode *N) {
SDValue N0 = N->getOperand(0);
+ EVT VT = N->getValueType(0);
+ // fold (bitreverse c1) -> c2
+ if (DAG.isConstantIntBuildVectorOrConstantInt(N0))
+ return DAG.getNode(ISD::BITREVERSE, SDLoc(N), VT, N0);
// fold (bitreverse (bitreverse x)) -> x
if (N0.getOpcode() == ISD::BITREVERSE)
return N0.getOperand(0);
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 37b90859685..6b2123f1940 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -3206,6 +3206,9 @@ SDValue SelectionDAG::getNode(unsigned Opcode, const SDLoc &DL, EVT VT,
if (VT == MVT::f128 && C->getValueType(0) == MVT::i128)
return getConstantFP(APFloat(APFloat::IEEEquad(), Val), DL, VT);
break;
+ case ISD::BITREVERSE:
+ return getConstant(Val.reverseBits(), DL, VT, C->isTargetOpcode(),
+ C->isOpaque());
case ISD::BSWAP:
return getConstant(Val.byteSwap(), DL, VT, C->isTargetOpcode(),
C->isOpaque());
@@ -3303,6 +3306,7 @@ SDValue SelectionDAG::getNode(unsigned Opcode, const SDLoc &DL, EVT VT,
case ISD::TRUNCATE:
case ISD::UINT_TO_FP:
case ISD::SINT_TO_FP:
+ case ISD::BITREVERSE:
case ISD::BSWAP:
case ISD::CTLZ:
case ISD::CTLZ_ZERO_UNDEF:
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