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group unsafe math folds together for easier reading
Also added a FIXME regarding redundant folds for non-canonicalized constants. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217390 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Sanjay Patel
parent
c3c0c6df2a
commit
f6ab875af0
@ -6557,177 +6557,169 @@ SDValue DAGCombiner::visitFADD(SDNode *N) {
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// fold (fadd c1, c2) -> c1 + c2
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if (N0CFP && N1CFP)
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return DAG.getNode(ISD::FADD, SDLoc(N), VT, N0, N1);
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// canonicalize constant to RHS
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if (N0CFP && !N1CFP)
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return DAG.getNode(ISD::FADD, SDLoc(N), VT, N1, N0);
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// fold (fadd A, 0) -> A
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if (Options.UnsafeFPMath && N1CFP && N1CFP->getValueAPF().isZero())
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return N0;
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// fold (fadd A, (fneg B)) -> (fsub A, B)
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if ((!LegalOperations || TLI.isOperationLegalOrCustom(ISD::FSUB, VT)) &&
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isNegatibleForFree(N1, LegalOperations, TLI, &Options) == 2)
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isNegatibleForFree(N1, LegalOperations, TLI, &Options) == 2)
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return DAG.getNode(ISD::FSUB, SDLoc(N), VT, N0,
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GetNegatedExpression(N1, DAG, LegalOperations));
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// fold (fadd (fneg A), B) -> (fsub B, A)
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if ((!LegalOperations || TLI.isOperationLegalOrCustom(ISD::FSUB, VT)) &&
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isNegatibleForFree(N0, LegalOperations, TLI, &Options) == 2)
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isNegatibleForFree(N0, LegalOperations, TLI, &Options) == 2)
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return DAG.getNode(ISD::FSUB, SDLoc(N), VT, N1,
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GetNegatedExpression(N0, DAG, LegalOperations));
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// If allowed, fold (fadd (fadd x, c1), c2) -> (fadd x, (fadd c1, c2))
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if (Options.UnsafeFPMath && N1CFP &&
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N0.getOpcode() == ISD::FADD && N0.getNode()->hasOneUse() &&
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isa<ConstantFPSDNode>(N0.getOperand(1)))
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return DAG.getNode(ISD::FADD, SDLoc(N), VT, N0.getOperand(0),
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DAG.getNode(ISD::FADD, SDLoc(N), VT,
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N0.getOperand(1), N1));
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// If 'unsafe math' is enabled, fold lots of things.
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if (Options.UnsafeFPMath) {
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// No FP constant should be created after legalization as Instruction
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// Selection pass has a hard time dealing with FP constants.
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bool AllowNewConst = (Level < AfterLegalizeDAG);
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// fold (fadd A, 0) -> A
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if (N1CFP && N1CFP->getValueAPF().isZero())
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return N0;
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// No FP constant should be created after legalization as Instruction
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// Selection pass has hard time in dealing with FP constant.
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//
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// We don't need test this condition for transformation like following, as
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// the DAG being transformed implies it is legal to take FP constant as
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// operand.
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//
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// (fadd (fmul c, x), x) -> (fmul c+1, x)
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//
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bool AllowNewFpConst = (Level < AfterLegalizeDAG);
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// fold (fadd (fadd x, c1), c2) -> (fadd x, (fadd c1, c2))
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if (N1CFP && N0.getOpcode() == ISD::FADD && N0.getNode()->hasOneUse() &&
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isa<ConstantFPSDNode>(N0.getOperand(1)))
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return DAG.getNode(ISD::FADD, SDLoc(N), VT, N0.getOperand(0),
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DAG.getNode(ISD::FADD, SDLoc(N), VT,
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N0.getOperand(1), N1));
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// If allowed, fold (fadd (fneg x), x) -> 0.0
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if (AllowNewConst && N0.getOpcode() == ISD::FNEG && N0.getOperand(0) == N1)
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return DAG.getConstantFP(0.0, VT);
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// If allowed, fold (fadd x, (fneg x)) -> 0.0
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if (AllowNewConst && N1.getOpcode() == ISD::FNEG && N1.getOperand(0) == N0)
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return DAG.getConstantFP(0.0, VT);
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// We can fold chains of FADD's of the same value into multiplications.
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// This transform is not safe in general because we are reducing the number
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// of rounding steps.
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// If allow, fold (fadd (fneg x), x) -> 0.0
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if (AllowNewFpConst && Options.UnsafeFPMath &&
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N0.getOpcode() == ISD::FNEG && N0.getOperand(0) == N1)
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return DAG.getConstantFP(0.0, VT);
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// FIXME: There are 4 redundant folds below where fmul canonicalization
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// should have moved the constant out of Op0?
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if (TLI.isOperationLegalOrCustom(ISD::FMUL, VT) && !N0CFP && !N1CFP) {
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if (N0.getOpcode() == ISD::FMUL) {
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ConstantFPSDNode *CFP00 = dyn_cast<ConstantFPSDNode>(N0.getOperand(0));
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ConstantFPSDNode *CFP01 = dyn_cast<ConstantFPSDNode>(N0.getOperand(1));
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// (fadd (fmul c, x), x) -> (fmul x, c+1)
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if (CFP00 && !CFP01 && N0.getOperand(1) == N1) {
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SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
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SDValue(CFP00, 0),
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DAG.getConstantFP(1.0, VT));
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return DAG.getNode(ISD::FMUL, SDLoc(N), VT, N1, NewCFP);
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}
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// (fadd (fmul x, c), x) -> (fmul x, c+1)
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if (CFP01 && !CFP00 && N0.getOperand(0) == N1) {
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SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
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SDValue(CFP01, 0),
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DAG.getConstantFP(1.0, VT));
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return DAG.getNode(ISD::FMUL, SDLoc(N), VT, N1, NewCFP);
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}
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// If allow, fold (fadd x, (fneg x)) -> 0.0
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if (AllowNewFpConst && Options.UnsafeFPMath &&
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N1.getOpcode() == ISD::FNEG && N1.getOperand(0) == N0)
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return DAG.getConstantFP(0.0, VT);
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// In unsafe math mode, we can fold chains of FADD's of the same value
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// into multiplications. This transform is not safe in general because
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// we are reducing the number of rounding steps.
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if (Options.UnsafeFPMath && TLI.isOperationLegalOrCustom(ISD::FMUL, VT) &&
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!N0CFP && !N1CFP) {
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if (N0.getOpcode() == ISD::FMUL) {
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ConstantFPSDNode *CFP00 = dyn_cast<ConstantFPSDNode>(N0.getOperand(0));
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ConstantFPSDNode *CFP01 = dyn_cast<ConstantFPSDNode>(N0.getOperand(1));
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// (fadd (fmul c, x), x) -> (fmul x, c+1)
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if (CFP00 && !CFP01 && N0.getOperand(1) == N1) {
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SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
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SDValue(CFP00, 0),
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DAG.getConstantFP(1.0, VT));
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return DAG.getNode(ISD::FMUL, SDLoc(N), VT,
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N1, NewCFP);
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// (fadd (fmul c, x), (fadd x, x)) -> (fmul x, c+2)
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if (CFP00 && !CFP01 && N1.getOpcode() == ISD::FADD &&
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N1.getOperand(0) == N1.getOperand(1) &&
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N0.getOperand(1) == N1.getOperand(0)) {
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SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
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SDValue(CFP00, 0),
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DAG.getConstantFP(2.0, VT));
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return DAG.getNode(ISD::FMUL, SDLoc(N), VT,
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N0.getOperand(1), NewCFP);
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}
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// (fadd (fmul x, c), (fadd x, x)) -> (fmul x, c+2)
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if (CFP01 && !CFP00 && N1.getOpcode() == ISD::FADD &&
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N1.getOperand(0) == N1.getOperand(1) &&
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N0.getOperand(0) == N1.getOperand(0)) {
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SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
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SDValue(CFP01, 0),
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DAG.getConstantFP(2.0, VT));
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return DAG.getNode(ISD::FMUL, SDLoc(N), VT,
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N0.getOperand(0), NewCFP);
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}
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}
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// (fadd (fmul x, c), x) -> (fmul x, c+1)
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if (CFP01 && !CFP00 && N0.getOperand(0) == N1) {
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SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
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SDValue(CFP01, 0),
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DAG.getConstantFP(1.0, VT));
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return DAG.getNode(ISD::FMUL, SDLoc(N), VT,
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N1, NewCFP);
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if (N1.getOpcode() == ISD::FMUL) {
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ConstantFPSDNode *CFP10 = dyn_cast<ConstantFPSDNode>(N1.getOperand(0));
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ConstantFPSDNode *CFP11 = dyn_cast<ConstantFPSDNode>(N1.getOperand(1));
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// (fadd x, (fmul c, x)) -> (fmul x, c+1)
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if (CFP10 && !CFP11 && N1.getOperand(1) == N0) {
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SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
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SDValue(CFP10, 0),
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DAG.getConstantFP(1.0, VT));
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return DAG.getNode(ISD::FMUL, SDLoc(N), VT, N0, NewCFP);
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}
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// (fadd x, (fmul x, c)) -> (fmul x, c+1)
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if (CFP11 && !CFP10 && N1.getOperand(0) == N0) {
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SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
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SDValue(CFP11, 0),
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DAG.getConstantFP(1.0, VT));
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return DAG.getNode(ISD::FMUL, SDLoc(N), VT, N0, NewCFP);
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}
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// (fadd (fadd x, x), (fmul c, x)) -> (fmul x, c+2)
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if (CFP10 && !CFP11 && N0.getOpcode() == ISD::FADD &&
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N0.getOperand(0) == N0.getOperand(1) &&
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N1.getOperand(1) == N0.getOperand(0)) {
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SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
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SDValue(CFP10, 0),
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DAG.getConstantFP(2.0, VT));
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return DAG.getNode(ISD::FMUL, SDLoc(N), VT, N1.getOperand(1), NewCFP);
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}
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// (fadd (fadd x, x), (fmul x, c)) -> (fmul x, c+2)
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if (CFP11 && !CFP10 && N0.getOpcode() == ISD::FADD &&
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N0.getOperand(0) == N0.getOperand(1) &&
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N1.getOperand(0) == N0.getOperand(0)) {
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SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
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SDValue(CFP11, 0),
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DAG.getConstantFP(2.0, VT));
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return DAG.getNode(ISD::FMUL, SDLoc(N), VT, N1.getOperand(0), NewCFP);
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}
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}
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// (fadd (fmul c, x), (fadd x, x)) -> (fmul x, c+2)
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if (CFP00 && !CFP01 && N1.getOpcode() == ISD::FADD &&
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N1.getOperand(0) == N1.getOperand(1) &&
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N0.getOperand(1) == N1.getOperand(0)) {
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SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
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SDValue(CFP00, 0),
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DAG.getConstantFP(2.0, VT));
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return DAG.getNode(ISD::FMUL, SDLoc(N), VT,
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N0.getOperand(1), NewCFP);
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if (N0.getOpcode() == ISD::FADD && AllowNewConst) {
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ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N0.getOperand(0));
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// (fadd (fadd x, x), x) -> (fmul x, 3.0)
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if (!CFP && N0.getOperand(0) == N0.getOperand(1) &&
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(N0.getOperand(0) == N1))
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return DAG.getNode(ISD::FMUL, SDLoc(N), VT,
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N1, DAG.getConstantFP(3.0, VT));
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}
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// (fadd (fmul x, c), (fadd x, x)) -> (fmul x, c+2)
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if (CFP01 && !CFP00 && N1.getOpcode() == ISD::FADD &&
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N1.getOperand(0) == N1.getOperand(1) &&
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N0.getOperand(0) == N1.getOperand(0)) {
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SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
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SDValue(CFP01, 0),
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DAG.getConstantFP(2.0, VT));
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return DAG.getNode(ISD::FMUL, SDLoc(N), VT,
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N0.getOperand(0), NewCFP);
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if (N1.getOpcode() == ISD::FADD && AllowNewConst) {
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ConstantFPSDNode *CFP10 = dyn_cast<ConstantFPSDNode>(N1.getOperand(0));
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// (fadd x, (fadd x, x)) -> (fmul x, 3.0)
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if (!CFP10 && N1.getOperand(0) == N1.getOperand(1) &&
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N1.getOperand(0) == N0)
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return DAG.getNode(ISD::FMUL, SDLoc(N), VT,
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N0, DAG.getConstantFP(3.0, VT));
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}
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}
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if (N1.getOpcode() == ISD::FMUL) {
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ConstantFPSDNode *CFP10 = dyn_cast<ConstantFPSDNode>(N1.getOperand(0));
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ConstantFPSDNode *CFP11 = dyn_cast<ConstantFPSDNode>(N1.getOperand(1));
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// (fadd x, (fmul c, x)) -> (fmul x, c+1)
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if (CFP10 && !CFP11 && N1.getOperand(1) == N0) {
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SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
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SDValue(CFP10, 0),
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DAG.getConstantFP(1.0, VT));
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return DAG.getNode(ISD::FMUL, SDLoc(N), VT,
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N0, NewCFP);
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}
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// (fadd x, (fmul x, c)) -> (fmul x, c+1)
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if (CFP11 && !CFP10 && N1.getOperand(0) == N0) {
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SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
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SDValue(CFP11, 0),
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DAG.getConstantFP(1.0, VT));
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return DAG.getNode(ISD::FMUL, SDLoc(N), VT,
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N0, NewCFP);
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}
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// (fadd (fadd x, x), (fmul c, x)) -> (fmul x, c+2)
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if (CFP10 && !CFP11 && N0.getOpcode() == ISD::FADD &&
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// (fadd (fadd x, x), (fadd x, x)) -> (fmul x, 4.0)
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if (AllowNewConst &&
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N0.getOpcode() == ISD::FADD && N1.getOpcode() == ISD::FADD &&
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N0.getOperand(0) == N0.getOperand(1) &&
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N1.getOperand(1) == N0.getOperand(0)) {
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SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
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SDValue(CFP10, 0),
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DAG.getConstantFP(2.0, VT));
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N1.getOperand(0) == N1.getOperand(1) &&
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N0.getOperand(0) == N1.getOperand(0))
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return DAG.getNode(ISD::FMUL, SDLoc(N), VT,
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N1.getOperand(1), NewCFP);
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}
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// (fadd (fadd x, x), (fmul x, c)) -> (fmul x, c+2)
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if (CFP11 && !CFP10 && N0.getOpcode() == ISD::FADD &&
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N0.getOperand(0) == N0.getOperand(1) &&
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N1.getOperand(0) == N0.getOperand(0)) {
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SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
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SDValue(CFP11, 0),
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DAG.getConstantFP(2.0, VT));
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return DAG.getNode(ISD::FMUL, SDLoc(N), VT,
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N1.getOperand(0), NewCFP);
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}
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N0.getOperand(0), DAG.getConstantFP(4.0, VT));
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}
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if (N0.getOpcode() == ISD::FADD && AllowNewFpConst) {
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ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N0.getOperand(0));
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// (fadd (fadd x, x), x) -> (fmul x, 3.0)
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if (!CFP && N0.getOperand(0) == N0.getOperand(1) &&
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(N0.getOperand(0) == N1))
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return DAG.getNode(ISD::FMUL, SDLoc(N), VT,
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N1, DAG.getConstantFP(3.0, VT));
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}
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if (N1.getOpcode() == ISD::FADD && AllowNewFpConst) {
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ConstantFPSDNode *CFP10 = dyn_cast<ConstantFPSDNode>(N1.getOperand(0));
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// (fadd x, (fadd x, x)) -> (fmul x, 3.0)
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if (!CFP10 && N1.getOperand(0) == N1.getOperand(1) &&
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N1.getOperand(0) == N0)
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return DAG.getNode(ISD::FMUL, SDLoc(N), VT,
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N0, DAG.getConstantFP(3.0, VT));
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}
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// (fadd (fadd x, x), (fadd x, x)) -> (fmul x, 4.0)
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if (AllowNewFpConst &&
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N0.getOpcode() == ISD::FADD && N1.getOpcode() == ISD::FADD &&
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N0.getOperand(0) == N0.getOperand(1) &&
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N1.getOperand(0) == N1.getOperand(1) &&
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N0.getOperand(0) == N1.getOperand(0))
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return DAG.getNode(ISD::FMUL, SDLoc(N), VT,
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N0.getOperand(0),
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DAG.getConstantFP(4.0, VT));
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}
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} // enable-unsafe-fp-math
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// FADD -> FMA combines:
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if ((Options.AllowFPOpFusion == FPOpFusion::Fast || Options.UnsafeFPMath) &&
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DAG.getTarget()
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