[llvm] [AVR] Adapt getPostIndexedAddressParts() and getPreIndexedAddressParts (PR #145040)

[Ben Shi via llvm-commits]

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@@ -1114,6 +1120,10 @@ bool AVRTargetLowering::getPostIndexedAddressParts(SDNode *N, SDNode *Op,
       if (AVR::isProgramMemoryAccess(LD))
         return false;
 
+    // Fixes https://github.com/llvm/llvm-project/issues/143247
----------------
benshi001 wrote:

For the above lines,

```
 // FIXME: We temporarily disable post increment load from program memory,
 //        due to bug https://github.com/llvm/llvm-project/issues/59914.
```

It is also a walkaround committed by me, it revealed the root cause, though did not fix the root cause.

I hope your walk around solution can also be like that.

https://github.com/llvm/llvm-project/pull/145040