[llvm-commits] [llvm] r82491 - in /llvm/trunk: lib/VMCore/Dominators.cpp test/Transforms/Mem2Reg/crash.ll

[Chris Lattner]

Author: lattner
Date: Mon Sep 21 17:39:35 2009
New Revision: 82491

URL: http://llvm.org/viewvc/llvm-project?rev=82491&view=rev
Log:
Fix PR5023: The instruction form of DominatorTree::dominates did not 
take into consideration that the result of an invoke is only valid in
the normal dest, not the unwind dest.  This caused 'PHINode::hasConstantValue'
to return true in an invalid situation, causing mem2reg to delete a phi that
was actually needed.  This caused a crash building 483.xalancbmk.


Added:
    llvm/trunk/test/Transforms/Mem2Reg/crash.ll
Modified:
    llvm/trunk/lib/VMCore/Dominators.cpp

Modified: llvm/trunk/lib/VMCore/Dominators.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/VMCore/Dominators.cpp?rev=82491&r1=82490&r2=82491&view=diff

==============================================================================
--- llvm/trunk/lib/VMCore/Dominators.cpp (original)
+++ llvm/trunk/lib/VMCore/Dominators.cpp Mon Sep 21 17:39:35 2009
@@ -52,10 +52,16 @@
   DT->print(OS);
 }
 
-// dominates - Return true if A dominates B. This performs the
+// dominates - Return true if A dominates a use in B. This performs the
 // special checks necessary if A and B are in the same basic block.
 bool DominatorTree::dominates(const Instruction *A, const Instruction *B) const{
   const BasicBlock *BBA = A->getParent(), *BBB = B->getParent();
+  
+  // If A is an invoke instruction, its value is only available in this normal
+  // successor block.
+  if (const InvokeInst *II = dyn_cast<InvokeInst>(A))
+    BBA = II->getNormalDest();
+  
   if (BBA != BBB) return dominates(BBA, BBB);
   
   // It is not possible to determine dominance between two PHI nodes 

Added: llvm/trunk/test/Transforms/Mem2Reg/crash.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/Mem2Reg/crash.ll?rev=82491&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/Mem2Reg/crash.ll (added)
+++ llvm/trunk/test/Transforms/Mem2Reg/crash.ll Mon Sep 21 17:39:35 2009
@@ -0,0 +1,24 @@
+; RUN: opt < %s -mem2reg -S
+; PR5023
+
+declare i32 @bar()
+
+define i32 @foo() {
+entry:
+  %whichFlag = alloca i32
+  %A = invoke i32 @bar()
+          to label %invcont2 unwind label %lpad86
+
+invcont2:
+  store i32 %A, i32* %whichFlag
+  br label %bb15
+
+bb15:
+  %B = load i32* %whichFlag
+  ret i32 %B
+
+lpad86:
+  br label %bb15
+  
+}
+