[LICM] Store sink and indirectbr instructions

Loop simplify skips exit-block insertion when exits contain indirectbr
instructions. This leads to an assertion in LICM when trying to sink
stores out of non-dedicated loop exits containing indirectbr
instructions. This patch fix this issue by re-checking for dedicated
exits in LICM prior to store sink attempts.

Differential Revision: http://reviews.llvm.org/D6414

rdar://problem/18943047

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222927 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Scalar/LICM.cpp

@@ -810,6 +810,7 @@ void LICM::PromoteAliasSet(AliasSet &AS,
   // us to prove better alignment.
   unsigned Alignment = 1;
   AAMDNodes AATags;
+  bool HasDedicatedExits = CurLoop->hasDedicatedExits();
 
   // Check that all of the pointers in the alias set have the same type.  We
   // cannot (yet) promote a memory location that is loaded and stored in
@@ -844,6 +845,11 @@ void LICM::PromoteAliasSet(AliasSet &AS,
         assert(!store->isVolatile() && "AST broken");
         if (!store->isSimple())
           return;
+        // Don't sink stores from loops without dedicated block exits. Exits
+        // containing indirect branches are not transformed by loop simplify,
+        // make sure we catch that.
+        if (!HasDedicatedExits)
+          return;
 
         // Note that we only check GuaranteedToExecute inside the store case
         // so that we do not introduce stores where they did not exist before