llvm-project

3cc311ab - [mlir][Transforms] Dialect Conversion: No target mat. for 1:N replacement (#117513)

[mlir][Transforms] Dialect Conversion: No target mat. for 1:N replacement (#117513) During a 1:N replacement (`applySignatureConversion` or `replaceOpWithMultiple`), the dialect conversion driver used to insert two materializations: * Argument materialization: convert N replacement values to 1 SSA value of the original type `S`. * Target materialization: convert original type to legalized type `T`. The target materialization is unnecessary. Subsequent patterns receive the replacement values via their adaptors. These patterns have their own type converter. When they see a replacement value of type `S`, they will automatically insert a target materialization to type `T`. There is no reason to do this already during the 1:N replacement. (The functionality used to be duplicated in `remapValues` and `insertNTo1Materialization`.) Special case: If a subsequent pattern does not have a type converter, it does *not* insert any target materializations. That's because the absence of a type converter indicates that the pattern does not care about type legality. Therefore, it is correct to pass an SSA value of type `S` (or any other type) to the pattern. Note: Most patterns in `TestPatterns.cpp` run without a type converter. To make sure that the tests still behave the same, some of these patterns now have a type converter. This commit is in preparation of adding 1:N support to the conversion value mapping. Before making any further changes to the mapping infrastructure, I'd like to make sure that the code base around it (that uses the mapping) is robust.