[Mlir-commits] [mlir] [mlir][Transforms] Dialect conversion: fix crash when converting detached region (PR #100633)

[River Riddle]

================
@@ -685,6 +685,35 @@ namespace {
 //===----------------------------------------------------------------------===//
 // Region-Block Rewrite Testing
 
+/// This pattern applies a signature conversion to a block inside a detached
+/// region.
+struct TestDetachedSignatureConversion : public ConversionPattern {
+  TestDetachedSignatureConversion(MLIRContext *ctx)
+      : ConversionPattern("test.detached_signature_conversion", /*benefit=*/1,
+                          ctx) {}
+
+  LogicalResult
+  matchAndRewrite(Operation *op, ArrayRef<Value> operands,
+                  ConversionPatternRewriter &rewriter) const final {
+    if (op->getNumRegions() != 1)
+      return failure();
+    OperationState state(op->getLoc(), "test.legal_op_with_region", operands,
+                         op->getResultTypes(), {}, BlockRange());
+    Region *newRegion = state.addRegion();
+    rewriter.inlineRegionBefore(op->getRegion(0), *newRegion,
+                                newRegion->begin());
+    TypeConverter::SignatureConversion result(newRegion->getNumArguments());
+    for (unsigned i = 0; i < newRegion->getNumArguments(); ++i) {
+      result.addInputs(i, rewriter.getF64Type());
+    }
----------------
River707 wrote:

```suggestion
    for (unsigned i = 0; i < newRegion->getNumArguments(); ++i)
      result.addInputs(i, rewriter.getF64Type());
```

https://github.com/llvm/llvm-project/pull/100633