[mlir] Add integer range inference analysis
This commit defines a dataflow analysis for integer ranges, which uses a newly-added InferIntRangeInterface to compute the lower and upper bounds on the results of an operation from the bounds on the arguments. The range inference is a flow-insensitive dataflow analysis that can be used to simplify code, such as by statically identifying bounds checks that cannot fail in order to eliminate them. The InferIntRangeInterface has one method, inferResultRanges(), which takes a vector of inferred ranges for each argument to an op implementing the interface and a callback allowing the implementation to define the ranges for each result. These ranges are stored as ConstantIntRanges, which hold the lower and upper bounds for a value. Bounds are tracked separately for the signed and unsigned interpretations of a value, which ensures that the impact of arithmetic overflows is correctly tracked during the analysis. The commit also adds a -test-int-range-inference pass to test the analysis until it is integrated into SCCP or otherwise exposed. Finally, this commit fixes some bugs relating to the handling of region iteration arguments and terminators in the data flow analysis framework. Depends on D124020 Depends on D124021 Reviewed By: rriddle, Mogball Differential Revision: https://reviews.llvm.org/D124023
Loading
Please sign in to comment