[PATCH] D144619: [WebAssembly] Skip implied bitmask operation in LowerShift

[Thomas Lively via Phabricator via llvm-commits]

tlively added a comment.

Thanks for the ping! Sorry this fell through the cracks.



================
Comment at: llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp:2307
+        MaskOp = LHS;
+    } else {
+      if (!isa<ConstantSDNode>(RHS.getNode()))
----------------
Do we have tests that cover the case where the mask op is not a vector?


================
Comment at: llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp:2311-2312
+
+      auto ConstantRHS = dyn_cast<ConstantSDNode>(RHS.getNode());
+      if (ConstantRHS->getAPIntValue() == MaskBits)
+        MaskOp = LHS;
----------------
IIUC, there's no guarantee that the cast succeeds, so we have to guard against null here.


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  https://reviews.llvm.org/D144619/new/

https://reviews.llvm.org/D144619