[PATCH] D28675: [DAGCombine] require UnsafeFPMath for re-association of addition

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added a comment.

Can you add a few new tests which do the combine just from the FMF flags?



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Comment at: lib/CodeGen/SelectionDAG/DAGCombiner.cpp:8128
     // fold (fadd (fma x, y, (fmul u, v)), z) -> (fma x, y (fma u, v, z))
+    // FIXME The UnsafeAlgebra flag should be propagated to FMA/FMAD, but FMF
+    // are currently only supported on binary nodes.
----------------
: after FIXME (same for the other places)


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Comment at: lib/CodeGen/SelectionDAG/DAGCombiner.cpp:8134
+        (Options.UnsafeFPMath || (N->getFlags()->hasUnsafeAlgebra() &&
+         N0.getNode()->getFlags()->hasUnsafeAlgebra()))) {
       return DAG.getNode(PreferredFusedOpcode, SL, VT,
----------------
I don't think you need the getNode here (and same for the rest


https://reviews.llvm.org/D28675