C++: QL CFG performance and tweaks #737
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This improves performance slightly by putting the parameters in the order in which they'll be needed in `qlCFGSuccessor`.
This recursive predicate is made faster by working around a known optimizer problem (QL-796) that causes the optimizer to insert extra type checks in recursive case even when they are only needed in the base case.
The QL CFG and extractor CFG are the same, so the test passes. Neither of them model that `ref` may or may not be destructed.
geoffw0
approved these changes
Jan 9, 2019
| // If `x` was true, `ref` refers to a temporary object whose lifetime was | ||
| // extended to coincide with `ref`. Before the function returns, it | ||
| // should destruct `ref` if and only if the first branch was taken in the | ||
| // ?: expression. |
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Yes, isn't it. @dave-bartolomeo told me yesterday that there were cases with ? : where the compiler would have to create a temporary variable to store which case was taken in order to know whether it should call a destructor. I fiddled around in Compiler Explorer until I got some code with branching around the destructor call. Is that example something like what you had in mind, @dave-bartolomeo?
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Is the failing test relevant? Otherwise I'm happy to merge this. |
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The failing test is broken. Language-Tests/CPP passes, which is sufficient. |
cklin
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May 20, 2022
Post-release preparation for codeql-cli-2.9.2
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The main change here is the second commit, which cuts 30% off the run time of the most expensive predicate in the CFG calculation.