clang-analyzer-core.UndefinedBinaryOperatorResult false-postive

[nick-potenski]

The clang-analyzer-core.UndefinedBinaryOperatorResult incorrectly assumes an std::array's size() function can return 0 when used as the condition in a for loop with an index even though the array's size is a compile-time constant. This causes the analysis to skip the loop's body and leads to a false-positive uninitialized variable. I have a simplified reproduction case in Compiler Explorer here: https://godbolt.org/z/jGb3dv1qP

[llvmbot]

@llvm/issue-subscribers-clang-static-analyzer

Author: Nick Potenski (nick-potenski)

The `clang-analyzer-core.UndefinedBinaryOperatorResult` incorrectly assumes an std::array's size() function can return 0 when used as the condition in a for loop with an index even though the array's size is a compile-time constant. This causes the analysis to skip the loop's body and leads to a false-positive uninitialized variable. I have a simplified reproduction case in Compiler Explorer here: https://godbolt.org/z/jGb3dv1qP