[llvm] r219130 - BFI: Improve assertion message, since it's actually firing

[Duncan P. N. Exon Smith]

Author: dexonsmith
Date: Mon Oct  6 12:42:00 2014
New Revision: 219130

URL: http://llvm.org/viewvc/llvm-project?rev=219130&view=rev
Log:
BFI: Improve assertion message, since it's actually firing

This assertion is firing because -loop-unroll is failing to preserve
-loop-info (see PR20987).  Improve it.

Modified:
    llvm/trunk/lib/Analysis/BlockFrequencyInfoImpl.cpp

Modified: llvm/trunk/lib/Analysis/BlockFrequencyInfoImpl.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/BlockFrequencyInfoImpl.cpp?rev=219130&r1=219129&r2=219130&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/BlockFrequencyInfoImpl.cpp (original)
+++ llvm/trunk/lib/Analysis/BlockFrequencyInfoImpl.cpp Mon Oct  6 12:42:00 2014
@@ -602,7 +602,8 @@ static void findIrreducibleHeaders(
       break;
     }
   }
-  assert(Headers.size() >= 2 && "Should be irreducible");
+  assert(Headers.size() >= 2 &&
+         "Expected irreducible CFG; -loop-info is likely invalid");
   if (Headers.size() == InSCC.size()) {
     // Every block is a header.
     std::sort(Headers.begin(), Headers.end());