[PATCH] D12719: ScalarEvolution assume hanging bugfix

[Piotr Padlewski via cfe-commits]

Prazek added inline comments.

================
Comment at: lib/Analysis/ScalarEvolution.cpp:6980
@@ -6991,1 +6979,3 @@
 
+  // Check conditions due to any @llvm.assume intrinsics.
+  for (auto &AssumeVH : AC.assumptions()) {
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nlewycky wrote:
> What is it about this check which is a problem? Or put another way, why is this not okay but the call to isImpliedCond on line 6956 is fine? The problem is recursion through isImpliedCond->getSCEV->..., right?
The problem is that the check wasn't covering assume loop which caused big hang.

Stacktrace looked more like this
(isImpliedCond -> getZeroExtendExpr -> isLoopBackedgeGuardedByCond) x much


http://reviews.llvm.org/D12719