[llvm-commits] [llvm] r133607 - /llvm/trunk/lib/CodeGen/TailDuplication.cpp

[Rafael Espindola]

Author: rafael
Date: Tue Jun 21 23:01:58 2011
New Revision: 133607

URL: http://llvm.org/viewvc/llvm-project?rev=133607&view=rev
Log:
Reenable the optimization added in 133415, but change the definition of a "simple" bb to
be one with only one unconditional branch and no phis. Duplicating the phis in this case
is possible, but requeres liveness analysis or breaking edges.

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

Modified: llvm/trunk/lib/CodeGen/TailDuplication.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/TailDuplication.cpp?rev=133607&r1=133606&r2=133607&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/TailDuplication.cpp (original)
+++ llvm/trunk/lib/CodeGen/TailDuplication.cpp Tue Jun 21 23:01:58 2011
@@ -568,9 +568,9 @@
 TailDuplicatePass::isSimpleBB(MachineBasicBlock *TailBB) {
   if (TailBB->succ_size() != 1)
     return false;
-  MachineBasicBlock::iterator I = TailBB->getFirstNonPHI();
+  MachineBasicBlock::iterator I = TailBB->begin();
   MachineBasicBlock::iterator E = TailBB->end();
-  while (I->isDebugValue() && I != E)
+  while (I != E && I->isDebugValue())
     ++I;
   if (I == E)
     return true;
@@ -712,7 +712,7 @@
   DenseSet<unsigned> UsedByPhi;
   getRegsUsedByPHIs(*TailBB, &UsedByPhi);
 
-  if (0 && isSimpleBB(TailBB))
+  if (isSimpleBB(TailBB))
     return duplicateSimpleBB(TailBB, TDBBs, UsedByPhi, Copies);
 
   // Iterate through all the unique predecessors and tail-duplicate this