[llvm-commits] [llvm] r91634 - in /llvm/trunk/lib/CodeGen: PHIElimination.cpp StrongPHIElimination.cpp

[Bill Wendling]

Author: void
Date: Thu Dec 17 17:42:32 2009
New Revision: 91634

URL: http://llvm.org/viewvc/llvm-project?rev=91634&view=rev
Log:
Turn off critical edge splitting for landing pads. The introduction of a
non-landing pad basic block as the successor to a block that ends in an
unconditional jump will cause block folding to remove the added block as a
successor. Thus eventually removing it AND the landing pad entirely. Critical
edge splitting is an optimization, so we can safely turn it off when dealing
with landing pads.

Modified:
    llvm/trunk/lib/CodeGen/PHIElimination.cpp
    llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp

Modified: llvm/trunk/lib/CodeGen/PHIElimination.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/PHIElimination.cpp?rev=91634&r1=91633&r2=91634&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/PHIElimination.cpp (original)
+++ llvm/trunk/lib/CodeGen/PHIElimination.cpp Thu Dec 17 17:42:32 2009
@@ -71,7 +71,7 @@
     Changed |= EliminatePHINodes(Fn, *I);
 
   // Remove dead IMPLICIT_DEF instructions.
-  for (SmallPtrSet<MachineInstr*,4>::iterator I = ImpDefs.begin(),
+  for (SmallPtrSet<MachineInstr*, 4>::iterator I = ImpDefs.begin(),
          E = ImpDefs.end(); I != E; ++I) {
     MachineInstr *DefMI = *I;
     unsigned DefReg = DefMI->getOperand(0).getReg();
@@ -83,8 +83,8 @@
   for (LoweredPHIMap::iterator I = LoweredPHIs.begin(), E = LoweredPHIs.end();
        I != E; ++I)
     Fn.DeleteMachineInstr(I->first);
-  LoweredPHIs.clear();
 
+  LoweredPHIs.clear();
   ImpDefs.clear();
   VRegPHIUseCount.clear();
   return Changed;
@@ -384,7 +384,8 @@
 bool llvm::PHIElimination::SplitPHIEdges(MachineFunction &MF,
                                          MachineBasicBlock &MBB,
                                          LiveVariables &LV) {
-  if (MBB.empty() || MBB.front().getOpcode() != TargetInstrInfo::PHI)
+  if (MBB.empty() || MBB.front().getOpcode() != TargetInstrInfo::PHI ||
+      MBB.isLandingPad())
     return false;   // Quick exit for basic blocks without PHIs.
 
   for (MachineBasicBlock::const_iterator BBI = MBB.begin(), BBE = MBB.end();

Modified: llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp?rev=91634&r1=91633&r2=91634&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp (original)
+++ llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp Thu Dec 17 17:42:32 2009
@@ -907,7 +907,7 @@
   
   // Determine which phi node operands need copies
   for (MachineFunction::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I)
-    if (!I->empty() &&
+    if (!I->empty() && !I->isLandingPad() &&
         I->begin()->getOpcode() == TargetInstrInfo::PHI)
       processBlock(I);