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[SM6.9] Prevent GVN from generating illegal integers - #9044
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Chris B (llvm-beanz) wants to merge 3 commits into
Open
Chris B (llvm-beanz) wants to merge 3 commits into
Chris B (llvm-beanz) wants to merge 3 commits into
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This change is a more complete set of checks to avoid GVN generating invalid integer sizes. We've had a few cases of this previously, but I think this covers the remaining cases in GVN. Fixes microsoft#9040
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🟢 Approval recommended
No blocking issues remain; the only finding is a minor release-note label typo.
1 open issue
What changed in this PR
Prevents GVN load forwarding from generating unsupported DXIL integer types, addressing #9040.
Changes:
- Checks integer widths and directly coerces equal-sized values.
- Adds regression tests for narrow and wide forwarding cases.
- Documents the compiler fix in release notes.
| File | Description |
|---|---|
| tools/clang/test/DXC/Passes/GVN/dxil_illegal_narrow_integer_size.ll | Tests narrow-width legality and valid forwarding. |
| tools/clang/test/DXC/Passes/GVN/dxil_illegal_integer_size.ll | Tests wide-vector forwarding and illegal intermediates. |
| lib/Transforms/Scalar/GVN.cpp | Guards coercions and avoids unnecessary integer intermediates. |
| docs/ReleaseNotes.md | Documents the GVN fix. |
Review effort: Balanced
Fixed issues related to GVN load forwarding, shader reflection, and optimizer crashes. Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
Damyan Pepper (damyanp)
approved these changes
Oct 18, 2026
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This change is a more complete set of checks to avoid GVN generating invalid integer sizes. We've had a few cases of this previously, but I think this covers the remaining cases in GVN.
Fixes #9040