[llvm] [RISCV] Combine ({s,u}{div,rem} (zext, zext)) -> (zext ({s,u}{div,rem} (zext, zext))) (PR #86779)

[Luke Lau via llvm-commits]

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@@ -12936,12 +12937,14 @@ static SDValue transformAddImmMulImm(SDNode *N, SelectionDAG &DAG,
 // add (zext, zext) -> zext (add (zext, zext))
 // sub (zext, zext) -> sext (sub (zext, zext))
 // mul (zext, zext) -> zext (mul (zext, zext))
+// sdiv (zext, zext) -> zext (sdiv (zext, zext))
+// udiv (zext, zext) -> zext (udiv (zext, zext))
+// srem (zext, zext) -> zext (srem (zext, zext))
+// urem (zext, zext) -> zext (urem (zext, zext))
 //
 // where the sum of the extend widths match, and the the range of the bin op
 // fits inside the width of the narrower bin op. (For profitability on rvv, we
 // use a power of two for both inner and outer extend.)
-//
-// TODO: Extend this to other binary ops
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lukel97 wrote:

On second thought, saturating arithmetic could probably benefit from this too?

https://github.com/llvm/llvm-project/pull/86779