Fix the issues originally addressed in r54070. After thinking about it some more, I realized that the right thing to do

is to have StrongPHIElimination use its knowledge of the PHIs before they're erased to update the intervals appropriate.  This is
both simpler and more accurate than the alternative, which was having LIA figure it out when it renumbered things, plus it's just
the right thing to do!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54077 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 19 insertions, 2 deletions

diff --git a/lib/CodeGen/StrongPHIElimination.cpp b/lib/CodeGen/StrongPHIElimination.cpp
index 7f98463..399e615 100644
--- a/lib/CodeGen/StrongPHIElimination.cpp
+++ b/lib/CodeGen/StrongPHIElimination.cpp
@@ -741,7 +741,7 @@ void StrongPHIElimination::ScheduleCopies(MachineBasicBlock* MBB,
   std::set<unsigned> RegHandled;
   for (SmallVector<std::pair<unsigned, MachineInstr*>, 4>::iterator I =
        InsertedPHIDests.begin(), E = InsertedPHIDests.end(); I != E; ++I)
-    if (!RegHandled.insert(I->first).second)
+    if (RegHandled.insert(I->first).second)
       LI.addLiveRangeToEndOfBlock(I->first, I->second);
 }
 
@@ -846,6 +846,19 @@ bool StrongPHIElimination::runOnMachineFunction(MachineFunction &Fn) {
        I != E; ) {
     MachineInstr* PInstr = *(I++);
     
+    // Trim live intervals of input registers.  They are no longer live into
+    // this block.
+    for (unsigned i = 1; i < PInstr->getNumOperands(); i += 2) {
+      unsigned reg = PInstr->getOperand(i).getReg();
+      MachineBasicBlock* MBB = PInstr->getOperand(i+1).getMBB();
+      LiveInterval& InputI = LI.getInterval(reg);
+      if (MBB != PInstr->getParent() &&
+          InputI.liveAt(LI.getMBBStartIdx(PInstr->getParent())))
+        InputI.removeRange(LI.getMBBStartIdx(PInstr->getParent()),
+                           LI.getInstructionIndex(PInstr),
+                           true);
+    }
+    
     // If this is a dead PHI node, then remove it from LiveIntervals.
     unsigned DestReg = PInstr->getOperand(0).getReg();
     LiveInterval& PI = LI.getInterval(DestReg);
@@ -860,7 +873,11 @@ bool StrongPHIElimination::runOnMachineFunction(MachineFunction &Fn) {
       // If the PHI is not dead, then the valno defined by the PHI
       // now has an unknown def.
       unsigned idx = LI.getDefIndex(LI.getInstructionIndex(PInstr));
-      PI.getLiveRangeContaining(idx)->valno->def = ~0U;
+      const LiveRange* PLR = PI.getLiveRangeContaining(idx);
+      PLR->valno->def = ~0U;
+      LiveRange R (LI.getMBBStartIdx(PInstr->getParent()),
+                   PLR->start, PLR->valno);
+      PI.addRange(R);
     }
     
     LI.RemoveMachineInstrFromMaps(PInstr);