[llvm] [SelectionDAG] Handle more opcodes in isGuaranteedNotToBeUndefOrPoison (PR #147019)

[Simon Pilgrim via llvm-commits]

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@@ -5458,6 +5458,83 @@ bool SelectionDAG::isGuaranteedNotToBeUndefOrPoison(SDValue Op,
     }
     return true;
 
+  case ISD::EXTRACT_SUBVECTOR: {
+    SDValue Src = Op.getOperand(0);
+    if (Src.getValueType().isScalableVector())
+      break;
+    uint64_t Idx = Op.getConstantOperandVal(1);
+    unsigned NumSrcElts = Src.getValueType().getVectorNumElements();
+    APInt DemandedSrcElts = DemandedElts.zext(NumSrcElts).shl(Idx);
+    return isGuaranteedNotToBeUndefOrPoison(Src, DemandedSrcElts, PoisonOnly,
+                                            Depth + 1);
+  }
+
+  case ISD::INSERT_SUBVECTOR: {
+    if (Op.getValueType().isScalableVector())
+      break;
+    SDValue Src = Op.getOperand(0);
+    SDValue Sub = Op.getOperand(1);
+    uint64_t Idx = Op.getConstantOperandVal(2);
+    unsigned NumSubElts = Sub.getValueType().getVectorNumElements();
+    APInt DemandedSubElts = DemandedElts.extractBits(NumSubElts, Idx);
+    APInt DemandedSrcElts = DemandedElts;
+    DemandedSrcElts.clearBits(Idx, Idx + NumSubElts);
+
+    if (!!DemandedSubElts && !isGuaranteedNotToBeUndefOrPoison(
+                                 Sub, DemandedSubElts, PoisonOnly, Depth + 1))
+      return false;
+    if (!!DemandedSrcElts && !isGuaranteedNotToBeUndefOrPoison(
+                                 Src, DemandedSrcElts, PoisonOnly, Depth + 1))
+      return false;
+    return true;
+  }
+
+  case ISD::EXTRACT_VECTOR_ELT: {
+    SDValue Src = Op.getOperand(0);
+    auto *IndexC = dyn_cast<ConstantSDNode>(Op.getOperand(1));
+    EVT SrcVT = Src.getValueType();
+    if (SrcVT.isFixedLengthVector() && IndexC &&
+        IndexC->getAPIntValue().ult(SrcVT.getVectorNumElements())) {
+      APInt DemandedSrcElts = APInt::getOneBitSet(SrcVT.getVectorNumElements(),
+                                                  IndexC->getZExtValue());
+      return isGuaranteedNotToBeUndefOrPoison(Src, DemandedSrcElts, PoisonOnly,
+                                              Depth + 1);
+    }
+    break;
+  }
+
+  case ISD::INSERT_VECTOR_ELT: {
+    SDValue InVec = Op.getOperand(0);
+    SDValue InVal = Op.getOperand(1);
+    SDValue EltNo = Op.getOperand(2);
+    EVT VT = InVec.getValueType();
+    auto *IndexC = dyn_cast<ConstantSDNode>(EltNo);
+    if (IndexC && VT.isFixedLengthVector() &&
+        IndexC->getZExtValue() < VT.getVectorNumElements()) {
----------------
RKSimon wrote:

`IndexC->getAPIntValue().ult(VT.getVectorNumElements())` (for consistency)

https://github.com/llvm/llvm-project/pull/147019