[PATCH] D28767: Do not verify Dominator tree if it has no roots

[Serge Pavlov via Phabricator via llvm-commits]

sepavloff added a comment.

> IIRC, when I wrote the patch to add the verifyDomTree function here it was taken verbatim from the IR level dominator tree verifier. Therefore, it might be a good idea to make a similar change to the IR-level verifier.

This change fixes 11 test fails observer when llvm was build with LLVM_ENABLE_EXPENSIVE_CHECKS turned on. None of them occurs in IR but some time ago there were such fails. So added the respective check.



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Comment at: lib/CodeGen/MachineDominators.cpp:147
+  if (getRoots().empty())
+    // If no roots found in the dominator tree, the pass that builds it is
+    // likely to be skipped.
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mcrosier wrote:
> I'd probably drop this comment in favor of the title of this revision, "Do not verify Dominator tree if it has no root." 
Rephrased the comment.


https://reviews.llvm.org/D28767