Fix a bug when hoist spill to a BB with landingpad successor.

This is to fix the bug in https://llvm.org/bugs/show_bug.cgi?id=27612.

When spill is hoisted to a BB with landingpad successor, and if the VNI
of the spill reg lives into the landingpad successor, the spill should be
inserted before the call which may throw exception. InsertPointAnalysis
is used to compute the safe insert point.

http://reviews.llvm.org/D20027 is a preparing patch for this patch.

Differential Revision: http://reviews.llvm.org/D19884.

llvm-svn: 269249

1 files changed, 10 insertions, 6 deletions

diff --git a/llvm/lib/CodeGen/InlineSpiller.cpp b/llvm/lib/CodeGen/InlineSpiller.cpp
index 6d2fcb9c358..1a62cad9cbb 100644
--- a/llvm/lib/CodeGen/InlineSpiller.cpp
+++ b/llvm/lib/CodeGen/InlineSpiller.cpp
@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "Spiller.h"
+#include "SplitKit.h"
 #include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/Statistic.h"
@@ -69,6 +70,8 @@ class HoistSpillHelper : private LiveRangeEdit::Delegate {
   const TargetRegisterInfo &TRI;
   const MachineBlockFrequencyInfo &MBFI;
 
+  InsertPointAnalysis IPA;
+
   // Map from StackSlot to its original register.
   DenseMap<int, unsigned> StackSlotToReg;
   // Map from pair of (StackSlot and Original VNI) to a set of spills which
@@ -114,7 +117,8 @@ public:
         MFI(*mf.getFrameInfo()), MRI(mf.getRegInfo()),
         TII(*mf.getSubtarget().getInstrInfo()),
         TRI(*mf.getSubtarget().getRegisterInfo()),
-        MBFI(pass.getAnalysis<MachineBlockFrequencyInfo>()) {}
+        MBFI(pass.getAnalysis<MachineBlockFrequencyInfo>()),
+        IPA(LIS, mf.getNumBlockIDs()) {}
 
   void addToMergeableSpills(MachineInstr *Spill, int StackSlot,
                             unsigned Original);
@@ -1075,7 +1079,7 @@ bool HoistSpillHelper::rmFromMergeableSpills(MachineInstr *Spill,
 bool HoistSpillHelper::isSpillCandBB(unsigned OrigReg, VNInfo &OrigVNI,
                                      MachineBasicBlock &BB, unsigned &LiveReg) {
   SlotIndex Idx;
-  MachineBasicBlock::iterator MI = BB.getFirstTerminator();
+  MachineBasicBlock::iterator MI = IPA.getLastInsertPointIter(BB);
   if (MI != BB.end())
     Idx = LIS.getInstructionIndex(*MI);
   else
@@ -1376,6 +1380,8 @@ void HoistSpillHelper::hoistAllSpills() {
   for (auto &Ent : MergeableSpills) {
     int Slot = Ent.first.first;
     unsigned OrigReg = SlotToOrigReg[Slot];
+    LiveInterval &OrigLI = LIS.getInterval(OrigReg);
+    IPA.setInterval(&OrigLI);
     VNInfo *OrigVNI = Ent.first.second;
     SmallPtrSet<MachineInstr *, 16> &EqValSpills = Ent.second;
     if (Ent.second.empty())
@@ -1408,17 +1414,15 @@ void HoistSpillHelper::hoistAllSpills() {
 
     // Stack live range update.
     LiveInterval &StackIntvl = LSS.getInterval(Slot);
-    if (!SpillsToIns.empty() || !SpillsToRm.empty()) {
-      LiveInterval &OrigLI = LIS.getInterval(OrigReg);
+    if (!SpillsToIns.empty() || !SpillsToRm.empty())
       StackIntvl.MergeValueInAsValue(OrigLI, OrigVNI,
                                      StackIntvl.getValNumInfo(0));
-    }
 
     // Insert hoisted spills.
     for (auto const Insert : SpillsToIns) {
       MachineBasicBlock *BB = Insert.first;
       unsigned LiveReg = Insert.second;
-      MachineBasicBlock::iterator MI = BB->getFirstTerminator();
+      MachineBasicBlock::iterator MI = IPA.getLastInsertPointIter(*BB);
       TII.storeRegToStackSlot(*BB, MI, LiveReg, false, Slot,
                               MRI.getRegClass(LiveReg), &TRI);
       LIS.InsertMachineInstrRangeInMaps(std::prev(MI), MI);