[llvm-commits] CVS: llvm/lib/Transforms/Utils/SimplifyCFG.cpp

[Chris Lattner]

Changes in directory llvm/lib/Transforms/Utils:

SimplifyCFG.cpp updated: 1.98 -> 1.99
---
Log message:

Fix PR867: http://llvm.org/PR867  (and maybe 868) and testcsae:
Transforms/SimplifyCFG/2006-08-03-Crash.ll



---
Diffs of the changes:  (+25 -6)

 SimplifyCFG.cpp |   31 +++++++++++++++++++++++++------
 1 files changed, 25 insertions(+), 6 deletions(-)


Index: llvm/lib/Transforms/Utils/SimplifyCFG.cpp
diff -u llvm/lib/Transforms/Utils/SimplifyCFG.cpp:1.98 llvm/lib/Transforms/Utils/SimplifyCFG.cpp:1.99
--- llvm/lib/Transforms/Utils/SimplifyCFG.cpp:1.98	Mon Jun 12 15:18:01 2006
+++ llvm/lib/Transforms/Utils/SimplifyCFG.cpp	Thu Aug  3 16:40:24 2006
@@ -459,12 +459,31 @@
 /// has no side effects, nuke it.  If it uses any instructions that become dead
 /// because the instruction is now gone, nuke them too.
 static void ErasePossiblyDeadInstructionTree(Instruction *I) {
-  if (isInstructionTriviallyDead(I)) {
-    std::vector<Value*> Operands(I->op_begin(), I->op_end());
-    I->getParent()->getInstList().erase(I);
-    for (unsigned i = 0, e = Operands.size(); i != e; ++i)
-      if (Instruction *OpI = dyn_cast<Instruction>(Operands[i]))
-        ErasePossiblyDeadInstructionTree(OpI);
+  if (!isInstructionTriviallyDead(I)) return;
+  
+  std::vector<Instruction*> InstrsToInspect;
+  InstrsToInspect.push_back(I);
+
+  while (!InstrsToInspect.empty()) {
+    I = InstrsToInspect.back();
+    InstrsToInspect.pop_back();
+
+    if (!isInstructionTriviallyDead(I)) continue;
+
+    // If I is in the work list multiple times, remove previous instances.
+    for (unsigned i = 0, e = InstrsToInspect.size(); i != e; ++i)
+      if (InstrsToInspect[i] == I) {
+        InstrsToInspect.erase(InstrsToInspect.begin()+i);
+        --i, --e;
+      }
+
+    // Add operands of dead instruction to worklist.
+    for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
+      if (Instruction *OpI = dyn_cast<Instruction>(I->getOperand(i)))
+        InstrsToInspect.push_back(OpI);
+
+    // Remove dead instruction.
+    I->eraseFromParent();
   }
 }