[Mlir-commits] [mlir] [mlir][Transforms] Fix mapping in `findOrBuildReplacementValue` (PR #121644)

[llvmlistbot at llvm.org]

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Author: Matthias Springer (matthias-springer)

<details>
<summary>Changes</summary>

Fixes two minor issues in `findOrBuildReplacementValue`:
* Remove a redundant `mapping.map`.
* Map `repl` instead of `value`. We used to overwrite an existing mapping, which could introduce extra materializations.

Note: We generally do not want to overwrite mappings, but create a chain of mappings. There are still a few more places, where a mapping is overwritten. Once those are fixed, I will put an assertion into `ConversionValueMapping::map`.

---
Full diff: https://github.com/llvm/llvm-project/pull/121644.diff


1 Files Affected:

- (modified) mlir/lib/Transforms/Utils/DialectConversion.cpp (+1-2) 


``````````diff
diff --git a/mlir/lib/Transforms/Utils/DialectConversion.cpp b/mlir/lib/Transforms/Utils/DialectConversion.cpp
index 6c3863e4c7f666..4904d3ce3f8635 100644
--- a/mlir/lib/Transforms/Utils/DialectConversion.cpp
+++ b/mlir/lib/Transforms/Utils/DialectConversion.cpp
@@ -1533,11 +1533,10 @@ Value ConversionPatternRewriterImpl::findOrBuildReplacementValue(
   Value castValue =
       buildUnresolvedMaterialization(MaterializationKind::Source,
                                      computeInsertPoint(repl), value.getLoc(),
-                                     /*valuesToMap=*/{value}, /*inputs=*/repl,
+                                     /*valuesToMap=*/repl, /*inputs=*/repl,
                                      /*outputType=*/value.getType(),
                                      /*originalType=*/Type(), converter)
           .front();
-  mapping.map(value, castValue);
   return castValue;
 }
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/121644