When the integer range analysis was first develop, a pass that did
integer range-based constant folding was developed and used as a test
pass. There was an intent to add such a folding to SCCP, but that hasn't
happened.
Meanwhile, -int-range-optimizations was added to the arith dialect's
transformations. The cmpi simplification in that pass is a strict subset
of the constant folding that lived in
-test-int-range-inference.
This commit moves the former test pass into -int-range-optimizaitons,
subsuming its previous contents. It also adds an optimization from
rocMLIR where `rem{s,u}i` operations that are noops are replaced by
their left operands.
This PR is in preparation to some extensions to the
`InferIntRangeInterface` around the `nsw` and `nuw` flags supported in
the `arith` dialect and LLVM.
We provide some common inference logic for `index` and `arith` in
`InferIntRangeCommon.h` but our Test Ops are currently fixed to `Index`
Types. As we test the range inference for arith Ops, especially around
the overflow behaviour, it's handy to have native support for the
typical integer types in the test Ops.
This patch
1. Changes the Attributes of `test.with_bounds` ops from `Index` to
`APInt` which matches the internal representation in
`ConstantIntRanges`.
2. Allows the use of `AnyInteger` in addition to `Index` for the
operands and results of the test Ops. This now requires explicit
specification of the type in the IR, where before `Index` was implicit.
3. Requires bounds Attrs to be specified in the precision of the SSA
value, eliminating any implicit truncation or extension. (*Could this
lead to problems?*)
This new features enabled to dedicate custom storage inline within operations.
This storage can be used as an alternative to attributes to store data that is
specific to an operation. Attribute can also be stored inside the properties
storage if desired, but any kind of data can be present as well. This offers
a way to store and mutate data without uniquing in the Context like Attribute.
See the OpPropertiesTest.cpp for an example where a struct with a
std::vector<> is attached to an operation and mutated in-place:
struct TestProperties {
int a = -1;
float b = -1.;
std::vector<int64_t> array = {-33};
};
More complex scheme (including reference-counting) are also possible.
The only constraint to enable storing a C++ object as "properties" on an
operation is to implement three functions:
- convert from the candidate object to an Attribute
- convert from the Attribute to the candidate object
- hash the object
Optional the parsing and printing can also be customized with 2 extra
functions.
A new options is introduced to ODS to allow dialects to specify:
let usePropertiesForAttributes = 1;
When set to true, the inherent attributes for all the ops in this dialect
will be using properties instead of being stored alongside discardable
attributes.
The TestDialect showcases this feature.
Another change is that we introduce new APIs on the Operation class
to access separately the inherent attributes from the discardable ones.
We envision deprecating and removing the `getAttr()`, `getAttrsDictionary()`,
and other similar method which don't make the distinction explicit, leading
to an entirely separate namespace for discardable attributes.
Recommit d572cd1b067f after fixing python bindings build.
Differential Revision: https://reviews.llvm.org/D141742
This new features enabled to dedicate custom storage inline within operations.
This storage can be used as an alternative to attributes to store data that is
specific to an operation. Attribute can also be stored inside the properties
storage if desired, but any kind of data can be present as well. This offers
a way to store and mutate data without uniquing in the Context like Attribute.
See the OpPropertiesTest.cpp for an example where a struct with a
std::vector<> is attached to an operation and mutated in-place:
struct TestProperties {
int a = -1;
float b = -1.;
std::vector<int64_t> array = {-33};
};
More complex scheme (including reference-counting) are also possible.
The only constraint to enable storing a C++ object as "properties" on an
operation is to implement three functions:
- convert from the candidate object to an Attribute
- convert from the Attribute to the candidate object
- hash the object
Optional the parsing and printing can also be customized with 2 extra
functions.
A new options is introduced to ODS to allow dialects to specify:
let usePropertiesForAttributes = 1;
When set to true, the inherent attributes for all the ops in this dialect
will be using properties instead of being stored alongside discardable
attributes.
The TestDialect showcases this feature.
Another change is that we introduce new APIs on the Operation class
to access separately the inherent attributes from the discardable ones.
We envision deprecating and removing the `getAttr()`, `getAttrsDictionary()`,
and other similar method which don't make the distinction explicit, leading
to an entirely separate namespace for discardable attributes.
Differential Revision: https://reviews.llvm.org/D141742
When `RegionBranchOpInterface::getSuccessorRegions` is called for anything other than the parent op, it expects the operands of the terminator of the source region to be passed, not the operands of the parent op. This was not always respected.
This fixes a bug in integer range inference and ForwardDataFlowSolver and changes `scf.while` to allow narrowing of successors using constant inputs.
Fixes#55873
Reviewed By: mehdi_amini, krzysz00
Differential Revision: https://reviews.llvm.org/D127261
This reverts commit 4e5ce2056e3e85f109a074e80bdd23a10ca2bed9.
This relands commit 1350c9887dca5ba80af8e3c1e61b29d6696eb240.
Reinstates the range analysis with the build issue fixed.
Differential Revision: https://reviews.llvm.org/D126926
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
