[llvm] [SelectionDAGBuilder] Propagate fast-math flags to fpext (PR #167574)

[Björn Pettersson via llvm-commits]

================
@@ -3976,7 +3976,10 @@ void SelectionDAGBuilder::visitFPExt(const User &I) {
   SDValue N = getValue(I.getOperand(0));
   EVT DestVT = DAG.getTargetLoweringInfo().getValueType(DAG.getDataLayout(),
                                                         I.getType());
-  setValue(&I, DAG.getNode(ISD::FP_EXTEND, getCurSDLoc(), DestVT, N));
+  SDNodeFlags Flags;
+  if (auto *TruncInst = dyn_cast<FPMathOperator>(&I))
----------------
bjope wrote:

TruncInst is confusing here (I guess it has been copied from somewhere). You could perhaps all it Operator or FPExtInst or something, but it seems like FPOp is a common variable name when dyn_cast-ing to a FPMathOperator. So I would suggest FPOp.

https://github.com/llvm/llvm-project/pull/167574