[Attributor] - Cap accesses in AAPointerInfo #1807
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bhandarkar-pranav wants to merge 2 commits intoamd-stagingfrom
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[Attributor] - Cap accesses in AAPointerInfo #1807bhandarkar-pranav wants to merge 2 commits intoamd-stagingfrom
bhandarkar-pranav wants to merge 2 commits intoamd-stagingfrom
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Add cl::opt -attributor-max-pi-accesses=<N> (default 0 = unlimited) that
caps the number of accesses in a single AAPointerInfo instance. When
AccessList.size() reaches the threshold in addAccess(), the instance is
set to pessimistic fixpoint.
This prevents O(N²) scaling in LTO builds with many GPU kernels sharing
runtime globals. Global-level AAPointerInfoFloating instances (e.g.,
@TeamState) accumulate direct accesses from all kernels in a partition,
and every query iterates the full list. With N kernels, this creates
O(N) accesses × O(N) queries = O(N²) cost.
On a VASP reproducer (11 patterns, ~160 kernels):
- No cap: 259s link time, 142s in forallInterferingAccesses
- cap=512: 65s link time, 3.4s in forallInterferingAccesses
- cap=128: 54s link time
No behavioral change when the flag is not set (default 0).
Tested: check-llvm (0 failures), check-flang (0 failures),
GPU Fortran correctness suite (0 regressions).
Made-with: Cursor
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