2 files changed, 272 insertions, 276 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 2b47407393d..9b678b22b46 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -785,252 +785,6 @@ void DAGCombiner::deleteAndRecombine(SDNode *N) {
   DAG.DeleteNode(N);
 }
 
-/// Return 1 if we can compute the negated form of the specified expression for
-/// the same cost as the expression itself, or 2 if we can compute the negated
-/// form more cheaply than the expression itself.
-static char isNegatibleForFree(SDValue Op, bool LegalOperations,
-                               const TargetLowering &TLI,
-                               const TargetOptions *Options,
-                               bool ForCodeSize,
-                               unsigned Depth = 0) {
-  // fneg is removable even if it has multiple uses.
-  if (Op.getOpcode() == ISD::FNEG)
-    return 2;
-
-  // Don't allow anything with multiple uses unless we know it is free.
-  EVT VT = Op.getValueType();
-  const SDNodeFlags Flags = Op->getFlags();
-  if (!Op.hasOneUse() &&
-      !(Op.getOpcode() == ISD::FP_EXTEND &&
-        TLI.isFPExtFree(VT, Op.getOperand(0).getValueType())))
-    return 0;
-
-  // Don't recurse exponentially.
-  if (Depth > SelectionDAG::MaxRecursionDepth)
-    return 0;
-
-  switch (Op.getOpcode()) {
-  default: return false;
-  case ISD::ConstantFP: {
-    if (!LegalOperations)
-      return 1;
-
-    // Don't invert constant FP values after legalization unless the target says
-    // the negated constant is legal.
-    return TLI.isOperationLegal(ISD::ConstantFP, VT) ||
-           TLI.isFPImmLegal(neg(cast<ConstantFPSDNode>(Op)->getValueAPF()), VT,
-                            ForCodeSize);
-  }
-  case ISD::BUILD_VECTOR: {
-    // Only permit BUILD_VECTOR of constants.
-    if (llvm::any_of(Op->op_values(), [&](SDValue N) {
-          return !N.isUndef() && !isa<ConstantFPSDNode>(N);
-        }))
-      return 0;
-    if (!LegalOperations)
-      return 1;
-    if (TLI.isOperationLegal(ISD::ConstantFP, VT) &&
-        TLI.isOperationLegal(ISD::BUILD_VECTOR, VT))
-      return 1;
-    return llvm::all_of(Op->op_values(), [&](SDValue N) {
-      return N.isUndef() ||
-             TLI.isFPImmLegal(neg(cast<ConstantFPSDNode>(N)->getValueAPF()), VT,
-                              ForCodeSize);
-    });
-  }
-  case ISD::FADD:
-    if (!Options->NoSignedZerosFPMath && !Flags.hasNoSignedZeros())
-      return 0;
-
-    // After operation legalization, it might not be legal to create new FSUBs.
-    if (LegalOperations && !TLI.isOperationLegalOrCustom(ISD::FSUB, VT))
-      return 0;
-
-    // fold (fneg (fadd A, B)) -> (fsub (fneg A), B)
-    if (char V = isNegatibleForFree(Op.getOperand(0), LegalOperations, TLI,
-                                    Options, ForCodeSize, Depth + 1))
-      return V;
-    // fold (fneg (fadd A, B)) -> (fsub (fneg B), A)
-    return isNegatibleForFree(Op.getOperand(1), LegalOperations, TLI, Options,
-                              ForCodeSize, Depth + 1);
-  case ISD::FSUB:
-    // We can't turn -(A-B) into B-A when we honor signed zeros.
-    if (!Options->NoSignedZerosFPMath && !Flags.hasNoSignedZeros())
-      return 0;
-
-    // fold (fneg (fsub A, B)) -> (fsub B, A)
-    return 1;
-
-  case ISD::FMUL:
-  case ISD::FDIV:
-    // fold (fneg (fmul X, Y)) -> (fmul (fneg X), Y) or (fmul X, (fneg Y))
-    if (char V = isNegatibleForFree(Op.getOperand(0), LegalOperations, TLI,
-                                    Options, ForCodeSize, Depth + 1))
-      return V;
-
-    // Ignore X * 2.0 because that is expected to be canonicalized to X + X.
-    if (auto *C = isConstOrConstSplatFP(Op.getOperand(1)))
-      if (C->isExactlyValue(2.0) && Op.getOpcode() == ISD::FMUL)
-        return 0;
-
-    return isNegatibleForFree(Op.getOperand(1), LegalOperations, TLI, Options,
-                              ForCodeSize, Depth + 1);
-
-  case ISD::FMA:
-  case ISD::FMAD: {
-    if (!Options->NoSignedZerosFPMath && !Flags.hasNoSignedZeros())
-      return 0;
-
-    // fold (fneg (fma X, Y, Z)) -> (fma (fneg X), Y, (fneg Z))
-    // fold (fneg (fma X, Y, Z)) -> (fma X, (fneg Y), (fneg Z))
-    char V2 = isNegatibleForFree(Op.getOperand(2), LegalOperations, TLI,
-                                 Options, ForCodeSize, Depth + 1);
-    if (!V2)
-      return 0;
-
-    // One of Op0/Op1 must be cheaply negatible, then select the cheapest.
-    char V0 = isNegatibleForFree(Op.getOperand(0), LegalOperations, TLI,
-                                 Options, ForCodeSize, Depth + 1);
-    char V1 = isNegatibleForFree(Op.getOperand(1), LegalOperations, TLI,
-                                 Options, ForCodeSize, Depth + 1);
-    char V01 = std::max(V0, V1);
-    return V01 ? std::max(V01, V2) : 0;
-  }
-
-  case ISD::FP_EXTEND:
-  case ISD::FP_ROUND:
-  case ISD::FSIN:
-    return isNegatibleForFree(Op.getOperand(0), LegalOperations, TLI, Options,
-                              ForCodeSize, Depth + 1);
-  }
-}
-
-/// If isNegatibleForFree returns true, return the newly negated expression.
-static SDValue GetNegatedExpression(SDValue Op, SelectionDAG &DAG,
-                                    bool LegalOperations, bool ForCodeSize,
-                                    unsigned Depth = 0) {
-  // fneg is removable even if it has multiple uses.
-  if (Op.getOpcode() == ISD::FNEG)
-    return Op.getOperand(0);
-
-  assert(Depth <= SelectionDAG::MaxRecursionDepth &&
-         "GetNegatedExpression doesn't match isNegatibleForFree");
-  const TargetOptions &Options = DAG.getTarget().Options;
-  const SDNodeFlags Flags = Op->getFlags();
-
-  switch (Op.getOpcode()) {
-  default: llvm_unreachable("Unknown code");
-  case ISD::ConstantFP: {
-    APFloat V = cast<ConstantFPSDNode>(Op)->getValueAPF();
-    V.changeSign();
-    return DAG.getConstantFP(V, SDLoc(Op), Op.getValueType());
-  }
-  case ISD::BUILD_VECTOR: {
-    SmallVector<SDValue, 4> Ops;
-    for (SDValue C : Op->op_values()) {
-      if (C.isUndef()) {
-        Ops.push_back(C);
-        continue;
-      }
-      APFloat V = cast<ConstantFPSDNode>(C)->getValueAPF();
-      V.changeSign();
-      Ops.push_back(DAG.getConstantFP(V, SDLoc(Op), C.getValueType()));
-    }
-    return DAG.getBuildVector(Op.getValueType(), SDLoc(Op), Ops);
-  }
-  case ISD::FADD:
-    assert((Options.NoSignedZerosFPMath || Flags.hasNoSignedZeros()) &&
-           "Expected NSZ fp-flag");
-
-    // fold (fneg (fadd A, B)) -> (fsub (fneg A), B)
-    if (isNegatibleForFree(Op.getOperand(0), LegalOperations,
-                           DAG.getTargetLoweringInfo(), &Options, ForCodeSize,
-                           Depth + 1))
-      return DAG.getNode(ISD::FSUB, SDLoc(Op), Op.getValueType(),
-                         GetNegatedExpression(Op.getOperand(0), DAG,
-                                              LegalOperations, ForCodeSize,
-                                              Depth + 1),
-                         Op.getOperand(1), Flags);
-    // fold (fneg (fadd A, B)) -> (fsub (fneg B), A)
-    return DAG.getNode(ISD::FSUB, SDLoc(Op), Op.getValueType(),
-                       GetNegatedExpression(Op.getOperand(1), DAG,
-                                            LegalOperations, ForCodeSize,
-                                            Depth + 1),
-                       Op.getOperand(0), Flags);
-  case ISD::FSUB:
-    // fold (fneg (fsub 0, B)) -> B
-    if (ConstantFPSDNode *N0CFP =
-            isConstOrConstSplatFP(Op.getOperand(0), /*AllowUndefs*/ true))
-      if (N0CFP->isZero())
-        return Op.getOperand(1);
-
-    // fold (fneg (fsub A, B)) -> (fsub B, A)
-    return DAG.getNode(ISD::FSUB, SDLoc(Op), Op.getValueType(),
-                       Op.getOperand(1), Op.getOperand(0), Flags);
-
-  case ISD::FMUL:
-  case ISD::FDIV:
-    // fold (fneg (fmul X, Y)) -> (fmul (fneg X), Y)
-    if (isNegatibleForFree(Op.getOperand(0), LegalOperations,
-                           DAG.getTargetLoweringInfo(), &Options, ForCodeSize,
-                           Depth + 1))
-      return DAG.getNode(Op.getOpcode(), SDLoc(Op), Op.getValueType(),
-                         GetNegatedExpression(Op.getOperand(0), DAG,
-                                              LegalOperations, ForCodeSize,
-                                              Depth + 1),
-                         Op.getOperand(1), Flags);
-
-    // fold (fneg (fmul X, Y)) -> (fmul X, (fneg Y))
-    return DAG.getNode(Op.getOpcode(), SDLoc(Op), Op.getValueType(),
-                       Op.getOperand(0),
-                       GetNegatedExpression(Op.getOperand(1), DAG,
-                                            LegalOperations, ForCodeSize,
-                                            Depth + 1), Flags);
-
-  case ISD::FMA:
-  case ISD::FMAD: {
-    assert((Options.NoSignedZerosFPMath || Flags.hasNoSignedZeros()) &&
-           "Expected NSZ fp-flag");
-
-    SDValue Neg2 = GetNegatedExpression(Op.getOperand(2), DAG, LegalOperations,
-                                        ForCodeSize, Depth + 1);
-
-    char V0 = isNegatibleForFree(Op.getOperand(0), LegalOperations,
-                                 DAG.getTargetLoweringInfo(), &Options,
-                                 ForCodeSize, Depth + 1);
-    char V1 = isNegatibleForFree(Op.getOperand(1), LegalOperations,
-                                 DAG.getTargetLoweringInfo(), &Options,
-                                 ForCodeSize, Depth + 1);
-    if (V0 >= V1) {
-      // fold (fneg (fma X, Y, Z)) -> (fma (fneg X), Y, (fneg Z))
-      SDValue Neg0 = GetNegatedExpression(
-          Op.getOperand(0), DAG, LegalOperations, ForCodeSize, Depth + 1);
-      return DAG.getNode(Op.getOpcode(), SDLoc(Op), Op.getValueType(), Neg0,
-                         Op.getOperand(1), Neg2, Flags);
-    }
-
-    // fold (fneg (fma X, Y, Z)) -> (fma X, (fneg Y), (fneg Z))
-    SDValue Neg1 = GetNegatedExpression(Op.getOperand(1), DAG, LegalOperations,
-                                        ForCodeSize, Depth + 1);
-    return DAG.getNode(Op.getOpcode(), SDLoc(Op), Op.getValueType(),
-                       Op.getOperand(0), Neg1, Neg2, Flags);
-  }
-
-  case ISD::FP_EXTEND:
-  case ISD::FSIN:
-    return DAG.getNode(Op.getOpcode(), SDLoc(Op), Op.getValueType(),
-                       GetNegatedExpression(Op.getOperand(0), DAG,
-                                            LegalOperations, ForCodeSize,
-                                            Depth + 1));
-  case ISD::FP_ROUND:
-    return DAG.getNode(ISD::FP_ROUND, SDLoc(Op), Op.getValueType(),
-                       GetNegatedExpression(Op.getOperand(0), DAG,
-                                            LegalOperations, ForCodeSize,
-                                            Depth + 1),
-                       Op.getOperand(1));
-  }
-}
-
 // APInts must be the same size for most operations, this helper
 // function zero extends the shorter of the pair so that they match.
 // We provide an Offset so that we can create bitwidths that won't overflow.
@@ -12052,17 +11806,17 @@ SDValue DAGCombiner::visitFADD(SDNode *N) {
 
   // fold (fadd A, (fneg B)) -> (fsub A, B)
   if ((!LegalOperations || TLI.isOperationLegalOrCustom(ISD::FSUB, VT)) &&
-      isNegatibleForFree(N1, LegalOperations, TLI, &Options, ForCodeSize) == 2)
-    return DAG.getNode(ISD::FSUB, DL, VT, N0,
-                       GetNegatedExpression(N1, DAG, LegalOperations,
-                                            ForCodeSize), Flags);
+      TLI.isNegatibleForFree(N1, DAG, LegalOperations, ForCodeSize) == 2)
+    return DAG.getNode(
+        ISD::FSUB, DL, VT, N0,
+        TLI.getNegatedExpression(N1, DAG, LegalOperations, ForCodeSize), Flags);
 
   // fold (fadd (fneg A), B) -> (fsub B, A)
   if ((!LegalOperations || TLI.isOperationLegalOrCustom(ISD::FSUB, VT)) &&
-      isNegatibleForFree(N0, LegalOperations, TLI, &Options, ForCodeSize) == 2)
-    return DAG.getNode(ISD::FSUB, DL, VT, N1,
-                       GetNegatedExpression(N0, DAG, LegalOperations,
-                                            ForCodeSize), Flags);
+      TLI.isNegatibleForFree(N0, DAG, LegalOperations, ForCodeSize) == 2)
+    return DAG.getNode(
+        ISD::FSUB, DL, VT, N1,
+        TLI.getNegatedExpression(N0, DAG, LegalOperations, ForCodeSize), Flags);
 
   auto isFMulNegTwo = [](SDValue FMul) {
     if (!FMul.hasOneUse() || FMul.getOpcode() != ISD::FMUL)
@@ -12241,16 +11995,16 @@ SDValue DAGCombiner::visitFSUB(SDNode *N) {
   if (N0CFP && N0CFP->isZero()) {
     if (N0CFP->isNegative() ||
         (Options.NoSignedZerosFPMath || Flags.hasNoSignedZeros())) {
-      if (isNegatibleForFree(N1, LegalOperations, TLI, &Options, ForCodeSize))
-        return GetNegatedExpression(N1, DAG, LegalOperations, ForCodeSize);
+      if (TLI.isNegatibleForFree(N1, DAG, LegalOperations, ForCodeSize))
+        return TLI.getNegatedExpression(N1, DAG, LegalOperations, ForCodeSize);
       if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT))
         return DAG.getNode(ISD::FNEG, DL, VT, N1, Flags);
     }
   }
 
   if (((Options.UnsafeFPMath && Options.NoSignedZerosFPMath) ||
-      (Flags.hasAllowReassociation() && Flags.hasNoSignedZeros()))
-      && N1.getOpcode() == ISD::FADD) {
+       (Flags.hasAllowReassociation() && Flags.hasNoSignedZeros())) &&
+      N1.getOpcode() == ISD::FADD) {
     // X - (X + Y) -> -Y
     if (N0 == N1->getOperand(0))
       return DAG.getNode(ISD::FNEG, DL, VT, N1->getOperand(1), Flags);
@@ -12260,10 +12014,10 @@ SDValue DAGCombiner::visitFSUB(SDNode *N) {
   }
 
   // fold (fsub A, (fneg B)) -> (fadd A, B)
-  if (isNegatibleForFree(N1, LegalOperations, TLI, &Options, ForCodeSize))
-    return DAG.getNode(ISD::FADD, DL, VT, N0,
-                       GetNegatedExpression(N1, DAG, LegalOperations,
-                                            ForCodeSize), Flags);
+  if (TLI.isNegatibleForFree(N1, DAG, LegalOperations, ForCodeSize))
+    return DAG.getNode(
+        ISD::FADD, DL, VT, N0,
+        TLI.getNegatedExpression(N1, DAG, LegalOperations, ForCodeSize), Flags);
 
   // FSUB -> FMA combines:
   if (SDValue Fused = visitFSUBForFMACombine(N)) {
@@ -12277,11 +12031,10 @@ SDValue DAGCombiner::visitFSUB(SDNode *N) {
 /// Return true if both inputs are at least as cheap in negated form and at
 /// least one input is strictly cheaper in negated form.
 bool DAGCombiner::isCheaperToUseNegatedFPOps(SDValue X, SDValue Y) {
-  const TargetOptions &Options = DAG.getTarget().Options;
-  if (char LHSNeg = isNegatibleForFree(X, LegalOperations, TLI, &Options,
-                                   ForCodeSize))
-    if (char RHSNeg = isNegatibleForFree(Y, LegalOperations, TLI, &Options,
-                                         ForCodeSize))
+  if (char LHSNeg =
+          TLI.isNegatibleForFree(X, DAG, LegalOperations, ForCodeSize))
+    if (char RHSNeg =
+            TLI.isNegatibleForFree(Y, DAG, LegalOperations, ForCodeSize))
       // Both negated operands are at least as cheap as their counterparts.
       // Check to see if at least one is cheaper negated.
       if (LHSNeg == 2 || RHSNeg == 2)
@@ -12362,8 +12115,10 @@ SDValue DAGCombiner::visitFMUL(SDNode *N) {
 
   // -N0 * -N1 --> N0 * N1
   if (isCheaperToUseNegatedFPOps(N0, N1)) {
-    SDValue NegN0 = GetNegatedExpression(N0, DAG, LegalOperations, ForCodeSize);
-    SDValue NegN1 = GetNegatedExpression(N1, DAG, LegalOperations, ForCodeSize);
+    SDValue NegN0 =
+        TLI.getNegatedExpression(N0, DAG, LegalOperations, ForCodeSize);
+    SDValue NegN1 =
+        TLI.getNegatedExpression(N1, DAG, LegalOperations, ForCodeSize);
     return DAG.getNode(ISD::FMUL, DL, VT, NegN0, NegN1, Flags);
   }
 
@@ -12445,8 +12200,10 @@ SDValue DAGCombiner::visitFMA(SDNode *N) {
 
   // (-N0 * -N1) + N2 --> (N0 * N1) + N2
   if (isCheaperToUseNegatedFPOps(N0, N1)) {
-    SDValue NegN0 = GetNegatedExpression(N0, DAG, LegalOperations, ForCodeSize);
-    SDValue NegN1 = GetNegatedExpression(N1, DAG, LegalOperations, ForCodeSize);
+    SDValue NegN0 =
+        TLI.getNegatedExpression(N0, DAG, LegalOperations, ForCodeSize);
+    SDValue NegN1 =
+        TLI.getNegatedExpression(N1, DAG, LegalOperations, ForCodeSize);
     return DAG.getNode(ISD::FMA, DL, VT, NegN0, NegN1, N2, Flags);
   }
 
@@ -12707,8 +12464,8 @@ SDValue DAGCombiner::visitFDIV(SDNode *N) {
   if (isCheaperToUseNegatedFPOps(N0, N1))
     return DAG.getNode(
         ISD::FDIV, SDLoc(N), VT,
-        GetNegatedExpression(N0, DAG, LegalOperations, ForCodeSize),
-        GetNegatedExpression(N1, DAG, LegalOperations, ForCodeSize), Flags);
+        TLI.getNegatedExpression(N0, DAG, LegalOperations, ForCodeSize),
+        TLI.getNegatedExpression(N1, DAG, LegalOperations, ForCodeSize), Flags);
 
   return SDValue();
 }
@@ -13262,9 +13019,8 @@ SDValue DAGCombiner::visitFNEG(SDNode *N) {
   if (isConstantFPBuildVectorOrConstantFP(N0))
     return DAG.getNode(ISD::FNEG, SDLoc(N), VT, N0);
 
-  if (isNegatibleForFree(N0, LegalOperations, DAG.getTargetLoweringInfo(),
-                         &DAG.getTarget().Options, ForCodeSize))
-    return GetNegatedExpression(N0, DAG, LegalOperations, ForCodeSize);
+  if (TLI.isNegatibleForFree(N0, DAG, LegalOperations, ForCodeSize))
+    return TLI.getNegatedExpression(N0, DAG, LegalOperations, ForCodeSize);
 
   // Transform fneg(bitconvert(x)) -> bitconvert(x ^ sign) to avoid loading
   // constant pool values.
diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index fbe4e8cca8e..0b6f8ba4257 100644
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -5331,6 +5331,246 @@ verifyReturnAddressArgumentIsConstant(SDValue Op, SelectionDAG &DAG) const {
   return false;
 }
 
+char TargetLowering::isNegatibleForFree(SDValue Op, SelectionDAG &DAG,
+                                        bool LegalOperations, bool ForCodeSize,
+                                        unsigned Depth) const {
+  // fneg is removable even if it has multiple uses.
+  if (Op.getOpcode() == ISD::FNEG)
+    return 2;
+
+  // Don't allow anything with multiple uses unless we know it is free.
+  EVT VT = Op.getValueType();
+  const SDNodeFlags Flags = Op->getFlags();
+  const TargetOptions &Options = DAG.getTarget().Options;
+  if (!Op.hasOneUse() && !(Op.getOpcode() == ISD::FP_EXTEND &&
+                           isFPExtFree(VT, Op.getOperand(0).getValueType())))
+    return 0;
+
+  // Don't recurse exponentially.
+  if (Depth > SelectionDAG::MaxRecursionDepth)
+    return 0;
+
+  switch (Op.getOpcode()) {
+  case ISD::ConstantFP: {
+    if (!LegalOperations)
+      return 1;
+
+    // Don't invert constant FP values after legalization unless the target says
+    // the negated constant is legal.
+    return isOperationLegal(ISD::ConstantFP, VT) ||
+           isFPImmLegal(neg(cast<ConstantFPSDNode>(Op)->getValueAPF()), VT,
+                        ForCodeSize);
+  }
+  case ISD::BUILD_VECTOR: {
+    // Only permit BUILD_VECTOR of constants.
+    if (llvm::any_of(Op->op_values(), [&](SDValue N) {
+          return !N.isUndef() && !isa<ConstantFPSDNode>(N);
+        }))
+      return 0;
+    if (!LegalOperations)
+      return 1;
+    if (isOperationLegal(ISD::ConstantFP, VT) &&
+        isOperationLegal(ISD::BUILD_VECTOR, VT))
+      return 1;
+    return llvm::all_of(Op->op_values(), [&](SDValue N) {
+      return N.isUndef() ||
+             isFPImmLegal(neg(cast<ConstantFPSDNode>(N)->getValueAPF()), VT,
+                          ForCodeSize);
+    });
+  }
+  case ISD::FADD:
+    if (!Options.NoSignedZerosFPMath && !Flags.hasNoSignedZeros())
+      return 0;
+
+    // After operation legalization, it might not be legal to create new FSUBs.
+    if (LegalOperations && !isOperationLegalOrCustom(ISD::FSUB, VT))
+      return 0;
+
+    // fold (fneg (fadd A, B)) -> (fsub (fneg A), B)
+    if (char V = isNegatibleForFree(Op.getOperand(0), DAG, LegalOperations,
+                                    ForCodeSize, Depth + 1))
+      return V;
+    // fold (fneg (fadd A, B)) -> (fsub (fneg B), A)
+    return isNegatibleForFree(Op.getOperand(1), DAG, LegalOperations,
+                              ForCodeSize, Depth + 1);
+  case ISD::FSUB:
+    // We can't turn -(A-B) into B-A when we honor signed zeros.
+    if (!Options.NoSignedZerosFPMath && !Flags.hasNoSignedZeros())
+      return 0;
+
+    // fold (fneg (fsub A, B)) -> (fsub B, A)
+    return 1;
+
+  case ISD::FMUL:
+  case ISD::FDIV:
+    // fold (fneg (fmul X, Y)) -> (fmul (fneg X), Y) or (fmul X, (fneg Y))
+    if (char V = isNegatibleForFree(Op.getOperand(0), DAG, LegalOperations,
+                                    ForCodeSize, Depth + 1))
+      return V;
+
+    // Ignore X * 2.0 because that is expected to be canonicalized to X + X.
+    if (auto *C = isConstOrConstSplatFP(Op.getOperand(1)))
+      if (C->isExactlyValue(2.0) && Op.getOpcode() == ISD::FMUL)
+        return 0;
+
+    return isNegatibleForFree(Op.getOperand(1), DAG, LegalOperations,
+                              ForCodeSize, Depth + 1);
+
+  case ISD::FMA:
+  case ISD::FMAD: {
+    if (!Options.NoSignedZerosFPMath && !Flags.hasNoSignedZeros())
+      return 0;
+
+    // fold (fneg (fma X, Y, Z)) -> (fma (fneg X), Y, (fneg Z))
+    // fold (fneg (fma X, Y, Z)) -> (fma X, (fneg Y), (fneg Z))
+    char V2 = isNegatibleForFree(Op.getOperand(2), DAG, LegalOperations,
+                                 ForCodeSize, Depth + 1);
+    if (!V2)
+      return 0;
+
+    // One of Op0/Op1 must be cheaply negatible, then select the cheapest.
+    char V0 = isNegatibleForFree(Op.getOperand(0), DAG, LegalOperations,
+                                 ForCodeSize, Depth + 1);
+    char V1 = isNegatibleForFree(Op.getOperand(1), DAG, LegalOperations,
+                                 ForCodeSize, Depth + 1);
+    char V01 = std::max(V0, V1);
+    return V01 ? std::max(V01, V2) : 0;
+  }
+
+  case ISD::FP_EXTEND:
+  case ISD::FP_ROUND:
+  case ISD::FSIN:
+    return isNegatibleForFree(Op.getOperand(0), DAG, LegalOperations,
+                              ForCodeSize, Depth + 1);
+  }
+
+  return 0;
+}
+
+SDValue TargetLowering::getNegatedExpression(SDValue Op, SelectionDAG &DAG,
+                                             bool LegalOperations,
+                                             bool ForCodeSize,
+                                             unsigned Depth) const {
+  // fneg is removable even if it has multiple uses.
+  if (Op.getOpcode() == ISD::FNEG)
+    return Op.getOperand(0);
+
+  assert(Depth <= SelectionDAG::MaxRecursionDepth &&
+         "getNegatedExpression doesn't match isNegatibleForFree");
+  const SDNodeFlags Flags = Op->getFlags();
+
+  switch (Op.getOpcode()) {
+  case ISD::ConstantFP: {
+    APFloat V = cast<ConstantFPSDNode>(Op)->getValueAPF();
+    V.changeSign();
+    return DAG.getConstantFP(V, SDLoc(Op), Op.getValueType());
+  }
+  case ISD::BUILD_VECTOR: {
+    SmallVector<SDValue, 4> Ops;
+    for (SDValue C : Op->op_values()) {
+      if (C.isUndef()) {
+        Ops.push_back(C);
+        continue;
+      }
+      APFloat V = cast<ConstantFPSDNode>(C)->getValueAPF();
+      V.changeSign();
+      Ops.push_back(DAG.getConstantFP(V, SDLoc(Op), C.getValueType()));
+    }
+    return DAG.getBuildVector(Op.getValueType(), SDLoc(Op), Ops);
+  }
+  case ISD::FADD:
+    assert((DAG.getTarget().Options.NoSignedZerosFPMath ||
+            Flags.hasNoSignedZeros()) &&
+           "Expected NSZ fp-flag");
+
+    // fold (fneg (fadd A, B)) -> (fsub (fneg A), B)
+    if (isNegatibleForFree(Op.getOperand(0), DAG, LegalOperations, ForCodeSize,
+                           Depth + 1))
+      return DAG.getNode(ISD::FSUB, SDLoc(Op), Op.getValueType(),
+                         getNegatedExpression(Op.getOperand(0), DAG,
+                                              LegalOperations, ForCodeSize,
+                                              Depth + 1),
+                         Op.getOperand(1), Flags);
+    // fold (fneg (fadd A, B)) -> (fsub (fneg B), A)
+    return DAG.getNode(ISD::FSUB, SDLoc(Op), Op.getValueType(),
+                       getNegatedExpression(Op.getOperand(1), DAG,
+                                            LegalOperations, ForCodeSize,
+                                            Depth + 1),
+                       Op.getOperand(0), Flags);
+  case ISD::FSUB:
+    // fold (fneg (fsub 0, B)) -> B
+    if (ConstantFPSDNode *N0CFP =
+            isConstOrConstSplatFP(Op.getOperand(0), /*AllowUndefs*/ true))
+      if (N0CFP->isZero())
+        return Op.getOperand(1);
+
+    // fold (fneg (fsub A, B)) -> (fsub B, A)
+    return DAG.getNode(ISD::FSUB, SDLoc(Op), Op.getValueType(),
+                       Op.getOperand(1), Op.getOperand(0), Flags);
+
+  case ISD::FMUL:
+  case ISD::FDIV:
+    // fold (fneg (fmul X, Y)) -> (fmul (fneg X), Y)
+    if (isNegatibleForFree(Op.getOperand(0), DAG, LegalOperations, ForCodeSize,
+                           Depth + 1))
+      return DAG.getNode(Op.getOpcode(), SDLoc(Op), Op.getValueType(),
+                         getNegatedExpression(Op.getOperand(0), DAG,
+                                              LegalOperations, ForCodeSize,
+                                              Depth + 1),
+                         Op.getOperand(1), Flags);
+
+    // fold (fneg (fmul X, Y)) -> (fmul X, (fneg Y))
+    return DAG.getNode(
+        Op.getOpcode(), SDLoc(Op), Op.getValueType(), Op.getOperand(0),
+        getNegatedExpression(Op.getOperand(1), DAG, LegalOperations,
+                             ForCodeSize, Depth + 1),
+        Flags);
+
+  case ISD::FMA:
+  case ISD::FMAD: {
+    assert((DAG.getTarget().Options.NoSignedZerosFPMath ||
+            Flags.hasNoSignedZeros()) &&
+           "Expected NSZ fp-flag");
+
+    SDValue Neg2 = getNegatedExpression(Op.getOperand(2), DAG, LegalOperations,
+                                        ForCodeSize, Depth + 1);
+
+    char V0 = isNegatibleForFree(Op.getOperand(0), DAG, LegalOperations,
+                                 ForCodeSize, Depth + 1);
+    char V1 = isNegatibleForFree(Op.getOperand(1), DAG, LegalOperations,
+                                 ForCodeSize, Depth + 1);
+    if (V0 >= V1) {
+      // fold (fneg (fma X, Y, Z)) -> (fma (fneg X), Y, (fneg Z))
+      SDValue Neg0 = getNegatedExpression(
+          Op.getOperand(0), DAG, LegalOperations, ForCodeSize, Depth + 1);
+      return DAG.getNode(Op.getOpcode(), SDLoc(Op), Op.getValueType(), Neg0,
+                         Op.getOperand(1), Neg2, Flags);
+    }
+
+    // fold (fneg (fma X, Y, Z)) -> (fma X, (fneg Y), (fneg Z))
+    SDValue Neg1 = getNegatedExpression(Op.getOperand(1), DAG, LegalOperations,
+                                        ForCodeSize, Depth + 1);
+    return DAG.getNode(Op.getOpcode(), SDLoc(Op), Op.getValueType(),
+                       Op.getOperand(0), Neg1, Neg2, Flags);
+  }
+
+  case ISD::FP_EXTEND:
+  case ISD::FSIN:
+    return DAG.getNode(Op.getOpcode(), SDLoc(Op), Op.getValueType(),
+                       getNegatedExpression(Op.getOperand(0), DAG,
+                                            LegalOperations, ForCodeSize,
+                                            Depth + 1));
+  case ISD::FP_ROUND:
+    return DAG.getNode(ISD::FP_ROUND, SDLoc(Op), Op.getValueType(),
+                       getNegatedExpression(Op.getOperand(0), DAG,
+                                            LegalOperations, ForCodeSize,
+                                            Depth + 1),
+                       Op.getOperand(1));
+  }
+
+  llvm_unreachable("Unknown code");
+}
+
 //===----------------------------------------------------------------------===//
 // Legalization Utilities
 //===----------------------------------------------------------------------===//