5 files changed, 31 insertions, 7 deletions

diff --git a/contrib/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/contrib/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index a5c0b7750410..5a9a8fba9647 100644
--- a/contrib/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/contrib/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -6191,7 +6191,7 @@ SDValue DAGCombiner::visitShiftByConstant(SDNode *N, ConstantSDNode *Amt) {
       return SDValue();
   }
 
-  if (!TLI.isDesirableToCommuteWithShift(LHS))
+  if (!TLI.isDesirableToCommuteWithShift(N, Level))
     return SDValue();
 
   // Fold the constants, shifting the binop RHS by the shift amount.
@@ -6495,7 +6495,8 @@ SDValue DAGCombiner::visitSHL(SDNode *N) {
   if ((N0.getOpcode() == ISD::ADD || N0.getOpcode() == ISD::OR) &&
       N0.getNode()->hasOneUse() &&
       isConstantOrConstantVector(N1, /* No Opaques */ true) &&
-      isConstantOrConstantVector(N0.getOperand(1), /* No Opaques */ true)) {
+      isConstantOrConstantVector(N0.getOperand(1), /* No Opaques */ true) &&
+      TLI.isDesirableToCommuteWithShift(N, Level)) {
     SDValue Shl0 = DAG.getNode(ISD::SHL, SDLoc(N0), VT, N0.getOperand(0), N1);
     SDValue Shl1 = DAG.getNode(ISD::SHL, SDLoc(N1), VT, N0.getOperand(1), N1);
     AddToWorklist(Shl0.getNode());
diff --git a/contrib/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/contrib/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index cfc7aa96d31f..75b8036779ba 100644
--- a/contrib/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/contrib/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -8496,7 +8496,9 @@ AArch64TargetLowering::getScratchRegisters(CallingConv::ID) const {
 }
 
 bool
-AArch64TargetLowering::isDesirableToCommuteWithShift(const SDNode *N) const {
+AArch64TargetLowering::isDesirableToCommuteWithShift(const SDNode *N,
+                                                     CombineLevel Level) const {
+  N = N->getOperand(0).getNode();
   EVT VT = N->getValueType(0);
     // If N is unsigned bit extraction: ((x >> C) & mask), then do not combine
     // it with shift to let it be lowered to UBFX.
diff --git a/contrib/llvm/lib/Target/AArch64/AArch64ISelLowering.h b/contrib/llvm/lib/Target/AArch64/AArch64ISelLowering.h
index d783c8a6048c..a6d66aeae043 100644
--- a/contrib/llvm/lib/Target/AArch64/AArch64ISelLowering.h
+++ b/contrib/llvm/lib/Target/AArch64/AArch64ISelLowering.h
@@ -363,7 +363,8 @@ public:
   const MCPhysReg *getScratchRegisters(CallingConv::ID CC) const override;
 
   /// Returns false if N is a bit extraction pattern of (X >> C) & Mask.
-  bool isDesirableToCommuteWithShift(const SDNode *N) const override;
+  bool isDesirableToCommuteWithShift(const SDNode *N,
+                                     CombineLevel Level) const override;
 
   /// Returns true if it is beneficial to convert a load of a constant
   /// to just the constant itself.
diff --git a/contrib/llvm/lib/Target/ARM/ARMISelLowering.cpp b/contrib/llvm/lib/Target/ARM/ARMISelLowering.cpp
index ede276dd91bb..a763e29b9f60 100644
--- a/contrib/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/contrib/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -10407,6 +10407,25 @@ static SDValue PerformADDCombineWithOperands(SDNode *N, SDValue N0, SDValue N1,
   return SDValue();
 }
 
+bool
+ARMTargetLowering::isDesirableToCommuteWithShift(const SDNode *N,
+                                                 CombineLevel Level) const {
+  if (Level == BeforeLegalizeTypes)
+    return true;
+
+  if (Subtarget->isThumb() && Subtarget->isThumb1Only())
+    return true;
+
+  if (N->getOpcode() != ISD::SHL)
+    return true;
+
+  // Turn off commute-with-shift transform after legalization, so it doesn't
+  // conflict with PerformSHLSimplify.  (We could try to detect when
+  // PerformSHLSimplify would trigger more precisely, but it isn't
+  // really necessary.)
+  return false;
+}
+
 static SDValue PerformSHLSimplify(SDNode *N,
                                 TargetLowering::DAGCombinerInfo &DCI,
                                 const ARMSubtarget *ST) {
@@ -10506,9 +10525,7 @@ static SDValue PerformSHLSimplify(SDNode *N,
   LLVM_DEBUG(dbgs() << "Simplify shl use:\n"; SHL.getOperand(0).dump();
              SHL.dump(); N->dump());
   LLVM_DEBUG(dbgs() << "Into:\n"; X.dump(); BinOp.dump(); Res.dump());
-
-  DAG.ReplaceAllUsesWith(SDValue(N, 0), Res);
-  return SDValue(N, 0);
+  return Res;
 }
 
 
diff --git a/contrib/llvm/lib/Target/ARM/ARMISelLowering.h b/contrib/llvm/lib/Target/ARM/ARMISelLowering.h
index 50b4c2977fb5..7e7016d1639c 100644
--- a/contrib/llvm/lib/Target/ARM/ARMISelLowering.h
+++ b/contrib/llvm/lib/Target/ARM/ARMISelLowering.h
@@ -583,6 +583,9 @@ class VectorType;
     unsigned getABIAlignmentForCallingConv(Type *ArgTy,
                                            DataLayout DL) const override;
 
+    bool isDesirableToCommuteWithShift(const SDNode *N,
+                                       CombineLevel Level) const override;
+
   protected:
     std::pair<const TargetRegisterClass *, uint8_t>
     findRepresentativeClass(const TargetRegisterInfo *TRI,