[llvm-commits] [llvm] r54535 - /llvm/trunk/lib/CodeGen/UnreachableBlockElim.cpp

[Owen Anderson]

Author: resistor
Date: Fri Aug  8 13:00:05 2008
New Revision: 54535

URL: http://llvm.org/viewvc/llvm-project?rev=54535&view=rev
Log:
Reduce the entries in a phi before testing it for deadness, because removing the entries might make it dead.

Modified:
    llvm/trunk/lib/CodeGen/UnreachableBlockElim.cpp

Modified: llvm/trunk/lib/CodeGen/UnreachableBlockElim.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/UnreachableBlockElim.cpp?rev=54535&r1=54534&r2=54535&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/UnreachableBlockElim.cpp (original)
+++ llvm/trunk/lib/CodeGen/UnreachableBlockElim.cpp Fri Aug  8 13:00:05 2008
@@ -152,6 +152,12 @@
     MachineBasicBlock::iterator phi = BB->begin();
     while (phi != BB->end() &&
            phi->getOpcode() == TargetInstrInfo::PHI) {
+      for (unsigned i = phi->getNumOperands() - 1; i >= 2; i-=2)
+        if (!preds.count(phi->getOperand(i).getMBB())) {
+          phi->RemoveOperand(i);
+          phi->RemoveOperand(i-1);
+        }
+      
       if (phi->getNumOperands() == 3) {
         unsigned Input = phi->getOperand(1).getReg();
         unsigned Output = phi->getOperand(0).getReg();
@@ -162,15 +168,9 @@
 
         if (Input != Output)
           F.getRegInfo().replaceRegWith(Output, Input);
-        
+
         continue;
       }
-      
-      for (unsigned i = phi->getNumOperands() - 1; i >= 2; i-=2)
-        if (!preds.count(phi->getOperand(i).getMBB())) {
-          phi->RemoveOperand(i);
-          phi->RemoveOperand(i-1);
-        }
   
       ++phi;
     }