[llvm] r280794 - [SimplifyCFG] Followup fix to r280790

[James Molloy via llvm-commits]

Author: jamesm
Date: Wed Sep  7 04:01:22 2016
New Revision: 280794

URL: http://llvm.org/viewvc/llvm-project?rev=280794&view=rev
Log:
[SimplifyCFG] Followup fix to r280790

In failure cases it's not guaranteed that the PHI we're inspecting is actually in the successor block! In this case we need to bail out early, and never query getIncomingValueForBlock() as that will cause an assert.

Modified:
    llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp

Modified: llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp?rev=280794&r1=280793&r2=280794&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp Wed Sep  7 04:01:22 2016
@@ -1401,9 +1401,11 @@ static bool canSinkInstructions(
   // we're contemplating sinking, it must already be determined to be sinkable.
   if (!isa<StoreInst>(I0)) {
     auto *PNUse = dyn_cast<PHINode>(*I0->user_begin());
-    if (!all_of(Insts, [&PNUse](const Instruction *I) -> bool {
+    auto *Succ = I0->getParent()->getTerminator()->getSuccessor(0);
+    if (!all_of(Insts, [&PNUse,&Succ](const Instruction *I) -> bool {
           auto *U = cast<Instruction>(*I->user_begin());
           return (PNUse &&
+                  PNUse->getParent() == Succ &&
                   PNUse->getIncomingValueForBlock(I->getParent()) == I) ||
                  U->getParent() == I->getParent();
         }))