[MLIR][Transforms] Fix dialect conversion inverse mapping (#104648)

Inverse mapping needs to be updated for the result that was remapped (it
was previously only updated halfway).

Author: zyx-billy

mlir/lib/Transforms/Utils/DialectConversion.cpp

@@ -2527,6 +2527,7 @@ LogicalResult OperationConverter::legalizeConvertedOpResultTypes(
           opReplacement->getConverter());
       rewriterImpl.mapping.map(result, castValue);
       inverseMapping[castValue].push_back(result);
+      llvm::erase(inverseMapping[newValue], result);
     }
   }
 

mlir/test/Transforms/test-legalize-target-materialization-no-uses.mlir

@@ -1,4 +1,4 @@
-// RUN: mlir-opt -test-target-materialization-with-no-uses %s | FileCheck %s
+// RUN: mlir-opt -test-target-materialization-with-no-uses -split-input-file %s | FileCheck %s
 
 // The conversion is set up as follows:
 // - type_changer ops are illegal;
@@ -25,3 +25,12 @@ func.func @foo() {
   "test.type_consumer"(%2) : (i64) -> ()
   return
 }
+
+// -----
+
+// CHECK-LABEL: @direct_forward
+func.func @direct_forward(%arg0 : i16) -> i16 {
+  // CHECK-NEXT: return
+  %0 = "test.type_changer"(%arg0) : (i16) -> i16
+  return %0 : i16
+}