[Mlir-commits] [mlir] [mlir][CFGToSCF] Fix crash when encountering unknown control flow ops (PR #184103)

[Mehdi Amini]

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@@ -1156,8 +1156,18 @@ static FailureOr<SmallVector<Block *>> transformToStructuredCFBranches(
     FailureOr<Operation *> result = interface.createStructuredBranchRegionOp(
         opBuilder, regionEntry->getTerminator(),
         continuation->getArgumentTypes(), conditionalRegions);
-    if (failed(result))
+    if (failed(result)) {
+      // Blocks were moved from the parent region into conditionalRegions before
+      // calling createStructuredBranchRegionOp. On failure, move them back to
+      // avoid use-after-free crashes: the moved blocks may still be referenced
+      // as successors by blocks remaining in the parent region, so destroying
+      // conditionalRegions with live uses would trigger an assertion.
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joker-eph wrote:

Yes, done!

https://github.com/llvm/llvm-project/pull/184103