[llvm] [SelectionDAG] Preserve fast math flags when legalizing/promoting (PR #130124)

[Harald van Dijk via llvm-commits]

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@@ -5075,6 +5075,9 @@ void SelectionDAGLegalize::PromoteNode(SDNode *Node) {
   if (Node->getOpcode() == ISD::BR_CC ||
       Node->getOpcode() == ISD::SELECT_CC)
     OVT = Node->getOperand(2).getSimpleValueType();
+  // Preserve fast math flags
+  SDNodeFlags FastMathFlags = Node->getFlags() & SDNodeFlags::FastMathFlags;
+  SelectionDAG::FlagInserter FlagsInserter(DAG, FastMathFlags);
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hvdijk wrote:

I'm not seeing where that happens below, but presumably, if that happens below somewhere, that is now no longer needed with this addition and could be cleaned up there, rather than here?

https://github.com/llvm/llvm-project/pull/130124