[llvm] [AVR] Fix codegen after getConstant assertions got enabled (PR #152269)

[via llvm-commits]

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@@ -713,7 +713,7 @@ SDValue AVRTargetLowering::getAVRCmp(SDValue LHS, SDValue RHS, ISD::CondCode CC,
     // Turn lhs < rhs with lhs constant into rhs >= lhs+1, this allows us to
     // fold the constant into the cmp instruction.
     if (const ConstantSDNode *C = dyn_cast<ConstantSDNode>(RHS)) {
-      RHS = DAG.getConstant(C->getSExtValue() + 1, DL, VT);
+      RHS = DAG.getSignedConstant(C->getSExtValue() + 1, DL, VT);
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aykevl wrote:

Looks like you are right. I changed it to `getConstant` and `getZExtValue` and it works (both the test I added and all TinyGo AVR tests pass with this patch applied).

https://github.com/llvm/llvm-project/pull/152269