Clang Static Analyzer and Strict Aliasing

Clang Frontend
1

Hi Cfe-dev,

I’m not particularly familiar with the clang static analzyer, so would like some help with a bug that was filed against it (when compiling for RISC-V, but I don’t think that’s the issue here, as the bug also shows up with the default target).

The bug is here: https://bugs.llvm.org/show_bug.cgi?id=47727

Is it expected that the static analzyer will catch (some?) strict aliasing issues like this?

Sam

2

Hi,

No, it shouldn’t reason or warn about strict aliasing. It potentially could and i’d love it to, but as of now it doesn’t. When it does, like in , it’s a bug in the static analyzer, namely yet another instance of . In particular, if you change one of the types to char (or something like that), it’ll bypass the strict aliasing rule and the analyzer would still emit a warning which would then be a definite false positive. I’ll reply to that bug report.

3

Thanks for the clarification! I’ll try to remember that when we get more Static Analyzer issues reported about RISC-V.

Sam