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

[Alkis Evlogimenos]

Changes in directory llvm/lib/CodeGen:

VirtRegMap.cpp updated: 1.5 -> 1.6

---
Log message:

Make spiller push stores right after the definition of a register so
that they are as far away from the loads as possible.


---
Diffs of the changes:  (+33 -8)

Index: llvm/lib/CodeGen/VirtRegMap.cpp
diff -u llvm/lib/CodeGen/VirtRegMap.cpp:1.5 llvm/lib/CodeGen/VirtRegMap.cpp:1.6
--- llvm/lib/CodeGen/VirtRegMap.cpp:1.5	Thu Feb 26 17:22:23 2004
+++ llvm/lib/CodeGen/VirtRegMap.cpp	Thu Feb 26 22:51:35 2004
@@ -23,6 +23,7 @@
 #include "llvm/Target/TargetInstrInfo.h"
 #include "Support/Statistic.h"
 #include "Support/Debug.h"
+#include "Support/DenseMap.h"
 #include "Support/STLExtras.h"
 #include <iostream>
 
@@ -73,6 +74,7 @@
     class Spiller {
         typedef std::vector<unsigned> Phys2VirtMap;
         typedef std::vector<bool> PhysFlag;
+        typedef DenseMap<MachineInstr*, VirtReg2IndexFunctor> Virt2MI;
 
         MachineFunction& mf_;
         const TargetMachine& tm_;
@@ -81,6 +83,7 @@
         const VirtRegMap& vrm_;
         Phys2VirtMap p2vMap_;
         PhysFlag dirty_;
+        Virt2MI lastDef_;
 
     public:
         Spiller(MachineFunction& mf, const VirtRegMap& vrm)
@@ -90,7 +93,8 @@
               mri_(*tm_.getRegisterInfo()),
               vrm_(vrm),
               p2vMap_(mri_.getNumRegs(), 0),
-              dirty_(mri_.getNumRegs(), false) {
+              dirty_(mri_.getNumRegs(), false),
+              lastDef_() {
             DEBUG(std::cerr << "********** REWRITE MACHINE CODE **********\n");
             DEBUG(std::cerr << "********** Function: "
                   << mf_.getFunction()->getName() << '\n');
@@ -99,11 +103,13 @@
         void eliminateVirtRegs() {
             for (MachineFunction::iterator mbbi = mf_.begin(),
                      mbbe = mf_.end(); mbbi != mbbe; ++mbbi) {
+                lastDef_.grow(mf_.getSSARegMap()->getLastVirtReg());
                 DEBUG(std::cerr << mbbi->getBasicBlock()->getName() << ":\n");
                 eliminateVirtRegsInMbb(*mbbi);
-                // clear map and dirty flag
+                // clear map, dirty flag and last ref
                 p2vMap_.assign(p2vMap_.size(), 0);
                 dirty_.assign(dirty_.size(), false);
+                lastDef_.clear();
             }
         }
 
@@ -113,11 +119,21 @@
                                unsigned physReg) {
             unsigned virtReg = p2vMap_[physReg];
             if (dirty_[physReg] && vrm_.hasStackSlot(virtReg)) {
-                mri_.storeRegToStackSlot(mbb, mii, physReg,
+                assert(lastDef_[virtReg] && "virtual register is mapped "
+                       "to a register and but was not defined!");
+                MachineBasicBlock::iterator lastDef = lastDef_[virtReg];
+                MachineBasicBlock::iterator nextLastRef = next(lastDef);
+                mri_.storeRegToStackSlot(*lastDef->getParent(),
+                                         nextLastRef,
+                                         physReg,
                                          vrm_.getStackSlot(virtReg),
                                          mri_.getRegClass(physReg));
                 ++numStores;
-                DEBUG(std::cerr << "*\t"; prior(mii)->print(std::cerr, tm_));
+                DEBUG(std::cerr << "\t\tadded: ";
+                      prior(nextLastRef)->print(std::cerr, tm_);
+                      std::cerr << "\t\tafter: ";
+                      lastDef->print(std::cerr, tm_));
+                lastDef_[virtReg] = 0;
             }
             p2vMap_[physReg] = 0;
             dirty_[physReg] = false;
@@ -145,7 +161,11 @@
                                               vrm_.getStackSlot(virtReg),
                                               mri_.getRegClass(physReg));
                     ++numLoads;
-                    DEBUG(std::cerr << "*\t"; prior(mii)->print(std::cerr,tm_));
+                    DEBUG(std::cerr << "\t\tadded: ";
+                          prior(mii)->print(std::cerr,tm_);
+                          std::cerr << "\t\tbefore: ";
+                          mii->print(std::cerr, tm_));
+                    lastDef_[virtReg] = mii;
                 }
             }
         }
@@ -160,6 +180,7 @@
 
             p2vMap_[physReg] = virtReg;
             dirty_[physReg] = true;
+            lastDef_[virtReg] = mii;
         }
 
         void eliminateVirtRegsInMbb(MachineBasicBlock& mbb) {
@@ -170,11 +191,15 @@
                     MachineOperand& op = mii->getOperand(i);
                     if (op.isRegister() && op.getReg() && op.isUse() &&
                         MRegisterInfo::isVirtualRegister(op.getReg())) {
-                        unsigned physReg = vrm_.getPhys(op.getReg());
-                        handleUse(mbb, mii, op.getReg(), physReg);
+                        unsigned virtReg = op.getReg();
+                        unsigned physReg = vrm_.getPhys(virtReg);
+                        handleUse(mbb, mii, virtReg, physReg);
                         mii->SetMachineOperandReg(i, physReg);
                         // mark as dirty if this is def&use
-                        if (op.isDef()) dirty_[physReg] = true;
+                        if (op.isDef()) {
+                            dirty_[physReg] = true;
+                            lastDef_[virtReg] = mii;
+                        }
                     }
                 }