[llvm] r174399 - Avoid using MRI::liveout_iterator for computing VRSAVEs.

[Jakob Stoklund Olesen]

Author: stoklund
Date: Tue Feb  5 11:40:36 2013
New Revision: 174399

URL: http://llvm.org/viewvc/llvm-project?rev=174399&view=rev
Log:
Avoid using MRI::liveout_iterator for computing VRSAVEs.

The liveout lists are about to be removed from MRI, this is the only
place they were used after register allocation.

Get the live out V registers directly from the return instructions
instead.

Modified:
    llvm/trunk/lib/Target/PowerPC/PPCFrameLowering.cpp

Modified: llvm/trunk/lib/Target/PowerPC/PPCFrameLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCFrameLowering.cpp?rev=174399&r1=174398&r2=174399&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/PPCFrameLowering.cpp (original)
+++ llvm/trunk/lib/Target/PowerPC/PPCFrameLowering.cpp Tue Feb  5 11:40:36 2013
@@ -119,12 +119,21 @@ static void HandleVRSaveUpdate(MachineIn
     if (VRRegNo[RegNo] == I->first)        // If this really is a vector reg.
       UsedRegMask &= ~(1 << (31-RegNo));   // Doesn't need to be marked.
   }
-  for (MachineRegisterInfo::liveout_iterator
-       I = MF->getRegInfo().liveout_begin(),
-       E = MF->getRegInfo().liveout_end(); I != E; ++I) {
-    unsigned RegNo = getPPCRegisterNumbering(*I);
-    if (VRRegNo[RegNo] == *I)              // If this really is a vector reg.
-      UsedRegMask &= ~(1 << (31-RegNo));   // Doesn't need to be marked.
+
+  // Live out registers appear as use operands on return instructions.
+  for (MachineFunction::const_iterator BI = MF->begin(), BE = MF->end();
+       UsedRegMask != 0 && BI != BE; ++BI) {
+    const MachineBasicBlock &MBB = *BI;
+    if (MBB.empty() || !MBB.back().isReturn())
+      continue;
+    const MachineInstr &Ret = MBB.back();
+    for (unsigned I = 0, E = Ret.getNumOperands(); I != E; ++I) {
+      const MachineOperand &MO = Ret.getOperand(I);
+      if (!MO.isReg() || !PPC::VRRCRegClass.contains(MO.getReg()))
+        continue;
+      unsigned RegNo = getPPCRegisterNumbering(MO.getReg());
+      UsedRegMask &= ~(1 << (31-RegNo));
+    }
   }
 
   // If no registers are used, turn this into a copy.