[PATCH] D52978: [TargetLowering][RISCV] Introduce isSExtCheaperThanZExt hook and implement for RISC-V

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

Makes sense.



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Comment at: lib/CodeGen/SelectionDAG/LegalizeTypes.h:284
 
+  SDValue SExtOrZExtPromotedInteger(SDValue Op) {
+    EVT OldVT = Op.getValueType();
----------------
This probably needs a doc-comment explaining that for a given subtarget and type, the choice of either sign-extension or zero-extension is consistent.


https://reviews.llvm.org/D52978