[llvm] r282175 - GVN-hoist: do not dereference null pointers

[Sebastian Pop via llvm-commits]

Author: spop
Date: Thu Sep 22 12:22:58 2016
New Revision: 282175

URL: http://llvm.org/viewvc/llvm-project?rev=282175&view=rev
Log:
GVN-hoist: do not dereference null pointers

there may be basic blocks without memory accesses, in which case the
list of accesses is a null pointer.

Modified:
    llvm/trunk/lib/Transforms/Scalar/GVNHoist.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/GVNHoist.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/GVNHoist.cpp?rev=282175&r1=282174&r2=282175&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/GVNHoist.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/GVNHoist.cpp Thu Sep 22 12:22:58 2016
@@ -338,6 +338,9 @@ private:
     bool ReachedNewPt = false;
     MemoryLocation DefLoc = MemoryLocation::get(OldPt);
     const MemorySSA::AccessList *Acc = MSSA->getBlockAccesses(BB);
+    if (!Acc)
+      return false;
+
     for (const MemoryAccess &MA : *Acc) {
       auto *MU = dyn_cast<MemoryUse>(&MA);
       if (!MU)