[Mlir-commits] [mlir] [mlir][Transforms] Dialect conversion: Fix missing source materialization (PR #97903)

[Johannes Reifferscheid]

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@@ -1388,20 +1379,24 @@ Block *ConversionPatternRewriterImpl::applySignatureConversion(
     if (replArgs.size() == 1 &&
         (!converter || replArgs[0].getType() == origArg.getType())) {
       newArg = replArgs.front();
+      mapping.map(origArg, newArg);
     } else {
-      Type origOutputType = origArg.getType();
-
-      // Legalize the argument output type.
-      Type outputType = origOutputType;
-      if (Type legalOutputType = converter->convertType(outputType))
-        outputType = legalOutputType;
-
-      newArg = buildUnresolvedArgumentMaterialization(
-          newBlock, origArg.getLoc(), replArgs, origOutputType, outputType,
-          converter);
+      // Build argument materialization: new block arguments -> old block
+      // argument type.
+      Value argMat = buildUnresolvedArgumentMaterialization(
+          newBlock, origArg.getLoc(), replArgs, origArg.getType(), converter);
+      mapping.map(origArg, argMat);
+
+      // Build target materialization: old block argument type -> legal type.
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jreiffers wrote:

Could you expand the comment to explain what it means for the converter to return null?

https://github.com/llvm/llvm-project/pull/97903