[PATCH] D131729: [RISCV] Move xori creation for scalar setccs to lowering.

[Craig Topper via Phabricator via llvm-commits]

craig.topper added inline comments.


================
Comment at: llvm/lib/Target/RISCV/RISCVISelLowering.cpp:3633
+          SDValue SetCC = DAG.getSetCC(
+              DL, VT, LHS, DAG.getConstant(Imm + 1, DL, OpVT), CCVal);
+          return DAG.getLogicalNOT(DL, SetCC, VT);
----------------
craig.topper wrote:
> reames wrote:
> > I'm not following something here.  You're increment the rhs of a GT or UGT in the manner I'd expect to apply to a GE or UGE, but also not changing the condition code?
> > 
> > This looks like a dag combine btw, why does this need to be done during lowering at all?
> The condition code was swapped on line 3623.
Prior to LegalizeDAG it would probably be reversed by DAGCombiner. I think there's an setcc+xor combine that only checks CondCodeLegal after LegalOperations. I could write an opposite DAGCombine that only runs after lowering?


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  https://reviews.llvm.org/D131729/new/

https://reviews.llvm.org/D131729