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

[Matthias Springer]

https://github.com/matthias-springer created https://github.com/llvm/llvm-project/pull/121644

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`.

>From 11026039f7ce600ff04fcf2e54a84035f4484678 Mon Sep 17 00:00:00 2001
From: Matthias Springer <mspringer at nvidia.com>
Date: Sat, 4 Jan 2025 13:37:30 +0100
Subject: [PATCH] [mlir][Transforms] Fix mapping in
 `findOrBuildReplacementValue`

Fixes two minor issues in `findOrBuildReplacementValue`:
* Remove a redundant `mapping.map`.
* Map `repl` instead of `value`. We used to overwrite an existing mapping, which may 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`.
---
 mlir/lib/Transforms/Utils/DialectConversion.cpp | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

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;
 }