JIT: guard overflow in loop cloning offset limits - #133834
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Positive array length offsets can wrap negative and let the fast clone run without bounds checks. Guard offsets that can overflow and add regression coverage for decreasing loops. Fixes dotnet#133823 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 336fb408-8580-4f7b-b3e6-087280a6294a
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🟢 Approval recommended
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Pull request overview
Guards JIT loop cloning against signed overflow in positive array-length offsets and adds regression coverage.
Changes:
- Adds overflow detection for positive offset limits.
- Tests decreasing loops using
>,>=, and!=.
File summaries
| File | Description |
|---|---|
src/tests/JIT/opt/Cloning/OffsetLimit.cs |
Adds positive-offset overflow regression tests. |
src/coreclr/jit/loopcloning.cpp |
Adds an overflow-aware fast-clone guard. |
Review details
- Files reviewed: 2/2 changed files
- Comments generated: 0
- Review effort level: Lite
This was referenced Sep 14, 2026
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Positive array length offsets can wrap negative and let the fast clone run
without bounds checks. Guard offsets that can overflow and add regression
coverage for decreasing loops.
Fixes #133823
Note
This pull request description was generated with GitHub Copilot.