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Fix the FIXME that was just added in r217390 - remove a bunch of redundant fold permutations. 

The testcases for these folds already exist in test/CodeGen/X86/fp-fast.ll.

llvm-svn: 217393
This commit is contained in:
Sanjay Patel 2014-09-08 18:22:51 +00:00
parent 553ac40f2e
commit f4b7a6b030
1 changed files with 2 additions and 43 deletions
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45
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -6602,22 +6602,11 @@ SDValue DAGCombiner::visitFADD(SDNode *N) {
// We can fold chains of FADD's of the same value into multiplications.
// This transform is not safe in general because we are reducing the number
// of rounding steps.
// FIXME: There are 4 redundant folds below where fmul canonicalization
// should have moved the constant out of Op0?
if (TLI.isOperationLegalOrCustom(ISD::FMUL, VT) && !N0CFP && !N1CFP) {
if (N0.getOpcode() == ISD::FMUL) {
ConstantFPSDNode *CFP00 = dyn_cast<ConstantFPSDNode>(N0.getOperand(0));
ConstantFPSDNode *CFP01 = dyn_cast<ConstantFPSDNode>(N0.getOperand(1));
// (fadd (fmul c, x), x) -> (fmul x, c+1)
if (CFP00 && !CFP01 && N0.getOperand(1) == N1) {
SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
SDValue(CFP00, 0),
DAG.getConstantFP(1.0, VT));
return DAG.getNode(ISD::FMUL, SDLoc(N), VT, N1, NewCFP);
}
// (fadd (fmul x, c), x) -> (fmul x, c+1)
if (CFP01 && !CFP00 && N0.getOperand(0) == N1) {
SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
@ -6625,17 +6614,6 @@ SDValue DAGCombiner::visitFADD(SDNode *N) {
DAG.getConstantFP(1.0, VT));
return DAG.getNode(ISD::FMUL, SDLoc(N), VT, N1, NewCFP);
}
// (fadd (fmul c, x), (fadd x, x)) -> (fmul x, c+2)
if (CFP00 && !CFP01 && N1.getOpcode() == ISD::FADD &&
N1.getOperand(0) == N1.getOperand(1) &&
N0.getOperand(1) == N1.getOperand(0)) {
SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
SDValue(CFP00, 0),
DAG.getConstantFP(2.0, VT));
return DAG.getNode(ISD::FMUL, SDLoc(N), VT,
N0.getOperand(1), NewCFP);
}
// (fadd (fmul x, c), (fadd x, x)) -> (fmul x, c+2)
if (CFP01 && !CFP00 && N1.getOpcode() == ISD::FADD &&
@ -6653,14 +6631,6 @@ SDValue DAGCombiner::visitFADD(SDNode *N) {
ConstantFPSDNode *CFP10 = dyn_cast<ConstantFPSDNode>(N1.getOperand(0));
ConstantFPSDNode *CFP11 = dyn_cast<ConstantFPSDNode>(N1.getOperand(1));
// (fadd x, (fmul c, x)) -> (fmul x, c+1)
if (CFP10 && !CFP11 && N1.getOperand(1) == N0) {
SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
SDValue(CFP10, 0),
DAG.getConstantFP(1.0, VT));
return DAG.getNode(ISD::FMUL, SDLoc(N), VT, N0, NewCFP);
}
// (fadd x, (fmul x, c)) -> (fmul x, c+1)
if (CFP11 && !CFP10 && N1.getOperand(0) == N0) {
SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
@ -6668,18 +6638,7 @@ SDValue DAGCombiner::visitFADD(SDNode *N) {
DAG.getConstantFP(1.0, VT));
return DAG.getNode(ISD::FMUL, SDLoc(N), VT, N0, NewCFP);
}
// (fadd (fadd x, x), (fmul c, x)) -> (fmul x, c+2)
if (CFP10 && !CFP11 && N0.getOpcode() == ISD::FADD &&
N0.getOperand(0) == N0.getOperand(1) &&
N1.getOperand(1) == N0.getOperand(0)) {
SDValue NewCFP = DAG.getNode(ISD::FADD, SDLoc(N), VT,
SDValue(CFP10, 0),
DAG.getConstantFP(2.0, VT));
return DAG.getNode(ISD::FMUL, SDLoc(N), VT, N1.getOperand(1), NewCFP);
}
// (fadd (fadd x, x), (fmul x, c)) -> (fmul x, c+2)
if (CFP11 && !CFP10 && N0.getOpcode() == ISD::FADD &&
N0.getOperand(0) == N0.getOperand(1) &&
@ -6690,7 +6649,7 @@ SDValue DAGCombiner::visitFADD(SDNode *N) {
return DAG.getNode(ISD::FMUL, SDLoc(N), VT, N1.getOperand(0), NewCFP);
}
}
if (N0.getOpcode() == ISD::FADD && AllowNewConst) {
ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N0.getOperand(0));
// (fadd (fadd x, x), x) -> (fmul x, 3.0)