[llvm] [DAG] computeKnownFPClass - add ISD::EXTRACT_SUBVECTOR/INSERT_SUBVECTOR handling. (PR #190378)

[via llvm-commits]

================
@@ -6102,6 +6100,50 @@ KnownFPClass SelectionDAG::computeKnownFPClass(SDValue Op,
     Known.fabs();
     break;
   }
+  case ISD::EXTRACT_SUBVECTOR: {
+    SDValue Src = Op.getOperand(0);
+    EVT SrcVT = Src.getValueType();
+    if (SrcVT.isFixedLengthVector()) {
+      unsigned Idx = Op.getConstantOperandVal(1);
+      unsigned NumSrcElts = SrcVT.getVectorNumElements();
+
+      APInt DemandedSrcElts = DemandedElts.zextOrTrunc(NumSrcElts).shl(Idx);
+      Known = computeKnownFPClass(Src, DemandedSrcElts, InterestedClasses,
+                                  Depth + 1);
+    } else
----------------
Xylecrack wrote:

done.

https://github.com/llvm/llvm-project/pull/190378