Allow readonly functions to unwind exceptions.  Teach
the optimizers about this.  For example, a readonly
function with no uses cannot be removed unless it is
also marked nounwind.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71071 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index eebac00..9feb442 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -12579,7 +12579,7 @@
   assert(I->hasOneUse() && "Invariants didn't hold!");
 
   // Cannot move control-flow-involving, volatile loads, vaarg, etc.
-  if (isa<PHINode>(I) || I->mayWriteToMemory() || isa<TerminatorInst>(I))
+  if (isa<PHINode>(I) || I->mayHaveSideEffects() || isa<TerminatorInst>(I))
     return false;
 
   // Do not sink alloca instructions out of the entry block.