[PATCH] D109214: [DAG] Fold setcc eq with ashr to compare to zero.

Jay Foad via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Wed Sep 8 03:54:54 PDT 2021


foad added inline comments.


================
Comment at: llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp:3921
+                          DAG.getConstant(0, dl, OpVT),
+                          Cond == ISD::SETEQ ? ISD::SETLT : ISD::SETGT);
+    }
----------------
uabelho wrote:
> The comment at line 3914 says we should use "setge" for the "setne" case, but the code actually use "SETGT"?
> 
> I'm seeing a miscompile with this patch for my out of tree target and I'm not sure what the problem actually is, but the difference between the comment and the code caught my eye.
Yes it should definitely be SETGE here!


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D109214/new/

https://reviews.llvm.org/D109214



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