[llvm-commits] CVS: llvm/lib/CodeGen/LiveIntervalAnalysis.cpp VirtRegMap.cpp VirtRegMap.h

[Evan Cheng]

Changes in directory llvm/lib/CodeGen:

LiveIntervalAnalysis.cpp updated: 1.154 -> 1.155
VirtRegMap.cpp updated: 1.60 -> 1.61
VirtRegMap.h updated: 1.18 -> 1.19
---
Log message:

Local spiller kills a store if the folded restore is turned into a copy.
But this is incorrect if the spilled value live range extends beyond the
current BB.
It is currently controlled by a temporary option -spiller-check-liveout.


---
Diffs of the changes:  (+21 -10)

 LiveIntervalAnalysis.cpp |    7 ++++---
 VirtRegMap.cpp           |   20 +++++++++++++++-----
 VirtRegMap.h             |    4 ++--
 3 files changed, 21 insertions(+), 10 deletions(-)


Index: llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
diff -u llvm/lib/CodeGen/LiveIntervalAnalysis.cpp:1.154 llvm/lib/CodeGen/LiveIntervalAnalysis.cpp:1.155
--- llvm/lib/CodeGen/LiveIntervalAnalysis.cpp:1.154	Sun Jan 22 17:41:00 2006
+++ llvm/lib/CodeGen/LiveIntervalAnalysis.cpp	Sun Apr 30 03:41:47 2006
@@ -271,14 +271,15 @@
             // can do this, we don't need to insert spill code.
             if (lv_)
               lv_->instructionChanged(MI, fmi);
-            vrm.virtFolded(li.reg, MI, i, fmi);
+            MachineBasicBlock &MBB = *MI->getParent();
+            bool LiveOut = li.liveAt(getInstructionIndex(&MBB.back()) +
+                                     InstrSlots::NUM);
+            vrm.virtFolded(li.reg, MI, i, fmi, LiveOut);
             mi2iMap_.erase(MI);
             i2miMap_[index/InstrSlots::NUM] = fmi;
             mi2iMap_[fmi] = index;
-            MachineBasicBlock &MBB = *MI->getParent();
             MI = MBB.insert(MBB.erase(MI), fmi);
             ++numFolded;
-
             // Folding the load/store can completely change the instruction in
             // unpredictable ways, rescan it from the beginning.
             goto for_operand;


Index: llvm/lib/CodeGen/VirtRegMap.cpp
diff -u llvm/lib/CodeGen/VirtRegMap.cpp:1.60 llvm/lib/CodeGen/VirtRegMap.cpp:1.61
--- llvm/lib/CodeGen/VirtRegMap.cpp:1.60	Thu Apr 27 23:43:18 2006
+++ llvm/lib/CodeGen/VirtRegMap.cpp	Sun Apr 30 03:41:47 2006
@@ -50,6 +50,10 @@
                         clEnumVal(local,  "  local spiller"),
                         clEnumValEnd),
              cl::init(local));
+
+  // TEMPORARY option to test a fix.
+  cl::opt<bool>
+  SpillerCheckLiveOut("spiller-check-liveout", cl::Hidden);
 }
 
 //===----------------------------------------------------------------------===//
@@ -81,7 +85,8 @@
 }
 
 void VirtRegMap::virtFolded(unsigned VirtReg, MachineInstr *OldMI,
-                            unsigned OpNo, MachineInstr *NewMI) {
+                            unsigned OpNo, MachineInstr *NewMI,
+                            bool LiveOut) {
   // Move previous memory references folded to new instruction.
   MI2VirtMapTy::iterator IP = MI2VirtMap.lower_bound(NewMI);
   for (MI2VirtMapTy::iterator I = MI2VirtMap.lower_bound(OldMI),
@@ -96,6 +101,7 @@
     MRInfo = isRef;
   } else {
     MRInfo = OldMI->getOperand(OpNo).isUse() ? isModRef : isMod;
+    if (LiveOut) MRInfo = (ModRef)(MRInfo | isLiveOut);
   }
 
   // add new memory reference
@@ -727,10 +733,14 @@
           MaybeDeadStores.erase(MDSI);
         else {
           // If we get here, the store is dead, nuke it now.
-          assert(MR == VirtRegMap::isMod && "Can't be modref!");
-          MBB.erase(MDSI->second);
-          MaybeDeadStores.erase(MDSI);
-          ++NumDSE;
+          assert(!(MR & VirtRegMap::isRef) && "Can't be modref!");
+          // Don't nuke it if the value is needed in another block.
+          if (!SpillerCheckLiveOut || !(MR & VirtRegMap::isLiveOut)) {
+            DEBUG(std::cerr << " Killed store:\t" << *MDSI->second);
+            MBB.erase(MDSI->second);
+            MaybeDeadStores.erase(MDSI);
+            ++NumDSE;
+          }
         }
       }
 


Index: llvm/lib/CodeGen/VirtRegMap.h
diff -u llvm/lib/CodeGen/VirtRegMap.h:1.18 llvm/lib/CodeGen/VirtRegMap.h:1.19
--- llvm/lib/CodeGen/VirtRegMap.h:1.18	Thu Apr 21 17:33:49 2005
+++ llvm/lib/CodeGen/VirtRegMap.h	Sun Apr 30 03:41:47 2006
@@ -26,7 +26,7 @@
 
   class VirtRegMap {
   public:
-    enum ModRef { isRef = 1, isMod = 2, isModRef = 3 };
+    enum ModRef { isRef = 1, isMod = 2, isModRef = 3, isLiveOut = 4 };
     typedef std::multimap<MachineInstr*,
                           std::pair<unsigned, ModRef> > MI2VirtMapTy;
 
@@ -128,7 +128,7 @@
     /// folded into newMI machine instruction.  The OpNum argument indicates the
     /// operand number of OldMI that is folded.
     void virtFolded(unsigned VirtReg, MachineInstr *OldMI, unsigned OpNum,
-                    MachineInstr *NewMI);
+                    MachineInstr *NewMI, bool LiveOut);
 
     /// @brief returns the virtual registers' values folded in memory
     /// operands of this instruction