[mlir][Transforms] Dialect conversion: Fix -debug crash

[matthias-springer]

Fix a crash in ConversionPatternRewriter::replaceUsesOfBlockArgument when running with -debug. The block that owns the block argument can be a detached block. In that case, do not attempt to print the name of the owner op.

[llvmbot]

@llvm/pr-subscribers-mlir

@llvm/pr-subscribers-mlir-core

Author: Matthias Springer (matthias-springer)

Changes

Fix a crash in ConversionPatternRewriter::replaceUsesOfBlockArgument when running with -debug. The block that owns the block argument can be a detached block. In that case, do not attempt to print the name of the owner op.

---

Full diff: https://github.com/llvm/llvm-project/pull/125660.diff

1 Files Affected:

• (modified) mlir/lib/Transforms/Utils/DialectConversion.cpp (+7-4)

diff --git a/mlir/lib/Transforms/Utils/DialectConversion.cpp b/mlir/lib/Transforms/Utils/DialectConversion.cpp
index 403321d40d53c9..7bfcd192c9aa9c 100644
--- a/mlir/lib/Transforms/Utils/DialectConversion.cpp
+++ b/mlir/lib/Transforms/Utils/DialectConversion.cpp
@@ -1708,10 +1708,13 @@ FailureOr<Block *> ConversionPatternRewriter::convertRegionTypes(
 void ConversionPatternRewriter::replaceUsesOfBlockArgument(BlockArgument from,
                                                            Value to) {
   LLVM_DEBUG({
-    Operation *parentOp = from.getOwner()->getParentOp();
-    impl->logger.startLine() << "** Replace Argument : '" << from
-                             << "'(in region of '" << parentOp->getName()
-                             << "'(" << from.getOwner()->getParentOp() << ")\n";
+    impl->logger.startLine() << "** Replace Argument : '" << from << "'";
+    if (Operation *parentOp = from.getOwner()->getParentOp()) {
+      impl->logger.getOStream() << " (in region of '" << parentOp->getName()
+                                << "' (" << parentOp << ")\n";
+    } else {
+      impl->logger.getOStream() << " (unlinked block)\n";
+    }
   });
   impl->appendRewrite<ReplaceBlockArgRewrite>(from.getOwner(), from,
                                               impl->currentTypeConverter);