[PATCH] D32596: [DAGCombine] Transform (fmul X, -2.0) --> (fneg (fadd X, X)).

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


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Comment at: lib/CodeGen/SelectionDAG/DAGCombiner.cpp:9583
+  // fold (fmul X, -2.0) -> (fneg (fadd X, X))
+  if (N1CFP && N1CFP->isExactlyValue(-2.0))
+    if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT)) {
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Only do this if isFNegFree()?


https://reviews.llvm.org/D32596