Misc improvements for rangecheck#129101
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- Fix unsound bounds in RangeOps::Or (could exclude reachable values); use max-based lower/upper bounds - Add UDIV constant-range support to GetRangeFromAssertionsWorker - Populate m_isVNNeverNegative on checked-bound / VN-relop assertions (and fix the operand used) - Restrict the never-negative O2K_VN_ADD_CNS range deduction to LT/LE relops (GT/GE were unsound) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Tagging subscribers to this area: @JulieLeeMSFT, @jakobbotsch |
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Pull request overview
This PR refines CoreCLR JIT range analysis and assertion metadata to both fix identified unsound deductions and modestly extend the set of VN operations that can be range-evaluated from assertions.
Changes:
- Fix
RangeOps::Orto produce sound bounds for bitwise OR over non-negative constant ranges by usingmax-based lower bounds and a conservative “fill lower bits” upper bound. - Extend
RangeCheck::GetRangeFromAssertionsWorkerto compute constant ranges forVNF_UDIV(unsigned division) when both operands have suitable constant ranges. - Improve assertion metadata by propagating
m_isVNNeverNegativeforO2K_VN_ADD_CNSin checked-bound and VN-relop assertions, and restrict a previously-unsound range deduction fast path to LT/LE-style relops.
Reviewed changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
| src/coreclr/jit/rangecheck.h | Adjusts OR range computation to avoid excluding reachable values; adds constant-range support for unsigned division. |
| src/coreclr/jit/rangecheck.cpp | Enables VNF_UDIV range evaluation from assertions; restricts a never-negative O2K_VN_ADD_CNS fast path to sound relops. |
| src/coreclr/jit/compiler.h | Populates O2K_VN_ADD_CNS::m_isVNNeverNegative based on VN analysis for checked-bound and VN-relop assertions. |
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PTAL @jakobbotsch @dotnet/jit-contrib a couple of improvements + 2 correctness fixes, diffs |
jakobbotsch
approved these changes
Jun 8, 2026
tannergooding
approved these changes
Jun 8, 2026
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RangeOps::Or(could exclude reachable values); usemax-based lower/upper bounds[3..5] | [4..7] -> lo = 3|4 = 7, hi = 5|7 = 7 (claims [7..7])UDIVconstant-range support toGetRangeFromAssertionsWorkerm_isVNNeverNegativeon checked-bound / VN-relop assertionsO2K_VN_ADD_CNSrange deduction to LT/LE relops (GT/GE were unsound)Diffs