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Disable the (A == (B-A)) -> 2*A == B xform when the sub has multiple uses (in
this case, the xform introduces an extra operation). This compiles PowerPC/compare-duplicate.ll into: _test: subf r2, r3, r4 cmplw cr0, r2, r3 bne cr0, LBB1_2 ;F instead of: _test: slwi r2, r3, 1 subf r3, r3, r4 cmplw cr0, r4, r2 bne cr0, LBB1_2 ;F This is target independent of course. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37246 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -1785,7 +1785,7 @@ TargetLowering::SimplifySetCC(MVT::ValueType VT, SDOperand N0, SDOperand N1,
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if (DAG.isCommutativeBinOp(N0.getOpcode()))
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return DAG.getSetCC(VT, N0.getOperand(0),
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DAG.getConstant(0, N0.getValueType()), Cond);
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else {
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else if (N0.Val->hasOneUse()) {
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assert(N0.getOpcode() == ISD::SUB && "Unexpected operation!");
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// (Z-X) == X --> Z == X<<1
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SDOperand SH = DAG.getNode(ISD::SHL, N1.getValueType(),
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