Krzysztof Drewniak f2e42d9324 [mlir][IntRangeInference] Handle ceildivsi(INT_MIN, x > 1) as expected (#116284) ...

Fixes #115293

While the definition of ceildivsi is integer division, rounding up, most
implementations will use `-(-a / b)` for dividing `a ceildiv b` with `a`
negative and `b` positive.

Mathematically, and for most integers, these two definitions are
equivalent. However, with `a == INT_MIN`, the initial negation is a
noop, which means that, while divinding and rounding up would give a
negative result, `-((- INT_MIN) / b)` is `-(INT_MIN / b)`, which is
positive.

This commit adds a special case to ceilDivSI inference to handle this
case and bring it in line with the operational instead of the
mathematical semantics of ceiling division.

2024-11-15 11:43:05 -06:00

29 KiB

Raw Blame History

View Raw