From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Sun, 26 Feb 2012 01:50:14 +0000 (+0000)
Subject: Don't call dominates on unreachable instructions.
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=8c727f9200cd54adc4a1b742950e80035bc53a20;p=oota-llvm.git

Don't call dominates on unreachable instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151466 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/llvm/Analysis/Dominators.h b/include/llvm/Analysis/Dominators.h
index b539a788a22..58730731473 100644
--- a/include/llvm/Analysis/Dominators.h
+++ b/include/llvm/Analysis/Dominators.h
@@ -820,7 +820,7 @@ public:
     DT->splitBlock(NewBB);
   }
 
-  bool isReachableFromEntry(const BasicBlock* A) {
+  bool isReachableFromEntry(const BasicBlock* A) const {
     return DT->isReachableFromEntry(A);
   }
 
diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp
index 37253f72cf6..b518d0ca71c 100644
--- a/lib/Analysis/InstructionSimplify.cpp
+++ b/lib/Analysis/InstructionSimplify.cpp
@@ -92,7 +92,8 @@ static bool ValueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) {
 
   // If we have a DominatorTree then do a precise test.
   if (DT)
-    return DT->dominates(I, P);
+    return !DT->isReachableFromEntry(P->getParent()) ||
+      !DT->isReachableFromEntry(I->getParent()) || DT->dominates(I, P);
 
   // Otherwise, if the instruction is in the entry block, and is not an invoke,
   // then it obviously dominates all phi nodes.