[PATCH] D156497: [BPF] Emit UNDEF rather than constant 0

[Yonghong Song via Phabricator via llvm-commits]

yonghong-song added inline comments.


================
Comment at: llvm/test/Bindings/llvm-c/many_args2.ll:12
+; Before this test was introduced, the BPF backend would generate incorrect-but-viable code
+; that would pass the verifier and violate user expectations at runtime.
+;
----------------
Could you explain what does the following mean?

```
Before this test was introduced, the BPF backend would generate incorrect-but-viable code that would pass the verifier and violate user expectations at runtime.
```


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Comment at: llvm/test/Bindings/llvm-c/struct_ret2.ll:7
+; Before this test was introduced, the BPF backend would generate incorrect-but-viable code
+; that would pass the verifier and violate user expectations at runtime.
+;
----------------
The same here. I guess I must miss something. Do you mean bpf backend generates incorrect code, or it detects incorrect condition but proceed and eventually report a success rather than a failure?
I must miss something here. 


Repository:
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  https://reviews.llvm.org/D156497/new/

https://reviews.llvm.org/D156497