From 7a25bd1d1950f39935afecdebf3c59d2b3f4eae4 Mon Sep 17 00:00:00 2001
From: Matthias Kramm <kramm@google.com>
Date: Mon, 2 Mar 2020 09:23:28 -0800
Subject: [PATCH] [mlir][DialectConversion] Abort early if a subregion has a
 disconnected CFG.

Summary:
Make computeConversionSet bubble up errors from nested regions. Note
that this doesn't change top-level behavior - since the nested region
calls emitError, the error was visible before, just not surfaced as
quickly.

Differential Revision: https://reviews.llvm.org/D75369
---
 mlir/lib/Transforms/DialectConversion.cpp | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/mlir/lib/Transforms/DialectConversion.cpp b/mlir/lib/Transforms/DialectConversion.cpp
index 8e1a9cc942bd..ed81b588875c 100644
--- a/mlir/lib/Transforms/DialectConversion.cpp
+++ b/mlir/lib/Transforms/DialectConversion.cpp
@@ -51,9 +51,11 @@ computeConversionSet(iterator_range<Region::iterator> region,
                                  : Optional<ConversionTarget::LegalOpDetails>();
       if (legalityInfo && legalityInfo->isRecursivelyLegal)
         continue;
-      for (auto &region : op.getRegions())
-        computeConversionSet(region.getBlocks(), region.getLoc(), toConvert,
-                             target);
+      for (auto &region : op.getRegions()) {
+        if (failed(computeConversionSet(region.getBlocks(), region.getLoc(),
+                                        toConvert, target)))
+          return failure();
+      }
     }
 
     // Recurse to children that haven't been visited.