[PATCH] D49837: [SelectionDAG] Handle unary SelectPatternFlavor for ABS case in SelectionDAGBuilder::visitSelect.

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


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Comment at: lib/CodeGen/SelectionDAG/TargetLowering.cpp:4458
+  SDValue Shift = DAG.getNode(ISD::SRA, dl, VT, Op,
+                              DAG.getConstant(VT.getScalarSizeInBits() - 1, dl, VT));
+  SDValue Add = DAG.getNode(ISD::ADD, dl, VT, Op, Shift);
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The shift constant needs to use a getShiftAmountTy type


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Comment at: lib/Target/ARM/ARMISelLowering.cpp:1210
+/*    for (auto &VT : {MVT::i8, MVT::i64})
+    setOperationAction(ISD::ABS, VT, Legal);*/
+    setTargetDAGCombine(ISD::ABS);
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Don't include commented out code


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Comment at: lib/Target/ARM/ARMISelLowering.cpp:10309
+
+    return DAG.getNode(ISD::XOR, DL, VT, Add, Shift);
+}
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Just call TargetLowering::expandABS ?


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Comment at: lib/Target/X86/X86ISelLowering.cpp:26030
+    Results.push_back(Lo);
+    Results.push_back(Hi);
+    return;
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Seems a shame this (and the ARM) code can't be put into the legalizers


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Comment at: test/CodeGen/Thumb/iabs.ll:76
+  ret i64 %abs
+}
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Add these new tests to trunk now so the patch shows the codegen diff


Repository:
  rL LLVM

https://reviews.llvm.org/D49837