Fix INT_MIN overflow in RangeCheck::BetweenBounds#127648
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EgorBo wants to merge 2 commits intodotnet:mainfrom
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Fix INT_MIN overflow in RangeCheck::BetweenBounds#127648EgorBo wants to merge 2 commits intodotnet:mainfrom
EgorBo wants to merge 2 commits intodotnet:mainfrom
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When the lower-limit constant 'lcns' equals INT_MIN, the expression '-lcns' triggers signed integer overflow (undefined behavior; on two's-complement targets it yields INT_MIN itself). The check '-lcns > arrSize' then evaluates to false and the function may incorrectly conclude that an out-of-bounds index is in range. Use 'lcns < -arrSize' instead. arrSize is guaranteed to be > 0 at these sites, so '-arrSize' cannot overflow. Fixes dotnet#127639 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Pull request overview
Fixes a signed-integer overflow corner case in the JIT range analysis (RangeCheck::BetweenBounds) when the lower-bound constant (lcns) is INT_MIN, which could previously cause an incorrect “in-bounds” result and lead to incorrect bounds-check elimination decisions.
Changes:
- Rewrites the comparison
-lcns > arrSizeto the mathematically equivalentlcns < -arrSizeto avoid negatingINT_MIN(undefined behavior in C++). - Applies the same fix to both relevant
lcnschecks inBetweenBounds, with explanatory comments.
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PTAL @dotnet/jit-contrib simple correctness change, no diffs. |
kg
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May 1, 2026
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fixes #127639