[llvm] [DAGCombine] Remove oneuse restrictions for RISCV in folding (shl (add_nsw x, c1)), c2) and folding (shl(sext(add x, c1)), c2) in some scenarios (PR #101294)

[Craig Topper via llvm-commits]

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@@ -17910,6 +17910,13 @@ AArch64TargetLowering::isDesirableToCommuteWithShift(const SDNode *N,
   SDValue ShiftLHS = N->getOperand(0);
   EVT VT = N->getValueType(0);
 
+  if (!ShiftLHS->hasOneUse())
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topperc wrote:

Does this logic need to be added to the default implementation of `isDesirableToCommuteWithShift` for targets that don't override it? I believe the default returns `true`

https://github.com/llvm/llvm-project/pull/101294