[UnrollRuntime] Add DomTree verification under debug mode

NFC: This adds the dom tree verification under debug mode at a point
just before we start unrolling the loop. This allows us to verify dom
tree at a state where it is much smaller and before the unrolling
actually happens.
This also implies we do not need to run -verify-dom-info everytime to
see if the DT is in a valid state when we transform the loop for runtime
unrolling.

llvm-svn: 350334

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp b/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
index 2981e6e2c52..a60becac649 100644
--- a/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
@@ -927,6 +927,12 @@ bool llvm::UnrollRuntimeLoopRemainder(Loop *L, unsigned Count,
   // of its parent loops, so the Scalar Evolution pass needs to be run again.
   SE->forgetTopmostLoop(L);
 
+  // Verify that the Dom Tree is correct.
+#if !defined(NDEBUG)
+  if (DT)
+    assert(DT->verify(DominatorTree::VerificationLevel::Full));
+#endif
+
   // Canonicalize to LoopSimplifyForm both original and remainder loops. We
   // cannot rely on the LoopUnrollPass to do this because it only does
   // canonicalization for parent/subloops and not the sibling loops.