[AVR] Fix codegen after getConstant assertions got enabled #152269
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Thanks for the quick review @benshi001! @RKSimon can you also take a look, to be sure? |
RKSimon
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Aug 6, 2025
| @@ -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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Should this be DAG.getConstant(C->getZExtValue() + 1, DL, VT); its an unsigned compare
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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).
I also added an assert to make sure the addition won't unintentionally overflow.
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✅ With the latest revision this PR passed the C/C++ code formatter. |
This fixes llvm#152097 This commit fixes two instances of a (somewhat) recently enabled assertion. One with a test, the other I can't reproduce (might be dead code) but certainly looks like an instance of the same problem. The PR that introduced the regression: llvm#117558
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Requested a backport for 21.x in #152679 |
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This fixes #152097
This commit fixes two instances of a (somewhat) recently enabled assertion. One with a test, the other I can't reproduce (might be dead code) but certainly looks like an instance of the same problem.
The PR that introduced the regression: #117558
With this patch, the AVR backend is usable again for TinyGo.