Allow targets to custom handle softening of results or operands before trying the...

[oota-llvm.git] / lib / CodeGen / RegAllocLinearScan.cpp

diff --git a/lib/CodeGen/RegAllocLinearScan.cpp b/lib/CodeGen/RegAllocLinearScan.cpp
index 2caa2f9d18021c08380fbc00eb6de0b305749f6a..fb9745262b7c16435af227a1afd2def9525d24ff 100644 (file)
--- a/lib/CodeGen/RegAllocLinearScan.cpp
+++ b/lib/CodeGen/RegAllocLinearScan.cpp
@@ -34,7 +34,10 @@
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <set>
 #include <queue>
@@ -142,6 +145,7 @@ namespace {
     }
 
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.setPreservesCFG();
       AU.addRequired<LiveIntervals>();
       if (StrongPHIElim)
         AU.addRequiredID(StrongPHIEliminationID);
@@ -235,7 +239,7 @@ namespace {
         }
       }
       if (Error)
-        abort();
+        llvm_unreachable(0);
 #endif
       regUse_.clear();
       regUseBackUp_.clear();
@@ -482,7 +486,8 @@ void RALinScan::linearScan()
 {
   // linear scan algorithm
   DOUT << "********** LINEAR SCAN **********\n";
-  DOUT << "********** Function: " << mf_->getFunction()->getName() << '\n';
+  DEBUG(errs() << "********** Function: " 
+        << mf_->getFunction()->getName() << '\n');
 
   DEBUG(printIntervals("fixed", fixed_.begin(), fixed_.end()));
 
@@ -545,26 +550,6 @@ void RALinScan::linearScan()
     if (!isPhys && vrm_->getPreSplitReg(cur.reg))
       continue;
 
-    // A register defined by an implicit_def can be liveout the def BB and livein
-    // to a use BB. Add it to the livein set of the use BB's.
-    if (!isPhys && cur.empty()) {
-      if (MachineInstr *DefMI = mri_->getVRegDef(cur.reg)) {
-        assert(DefMI->getOpcode() == TargetInstrInfo::IMPLICIT_DEF);
-        MachineBasicBlock *DefMBB = DefMI->getParent();
-        SmallPtrSet<MachineBasicBlock*, 4> Seen;
-        Seen.insert(DefMBB);
-        for (MachineRegisterInfo::reg_iterator ri = mri_->reg_begin(cur.reg),
-               re = mri_->reg_end(); ri != re; ++ri) {
-          MachineInstr *UseMI = &*ri;
-          MachineBasicBlock *UseMBB = UseMI->getParent();
-          if (Seen.insert(UseMBB)) {
-            assert(TargetRegisterInfo::isPhysicalRegister(Reg) &&
-                   "Adding a virtual register to livein set?");
-            UseMBB->addLiveIn(Reg);
-          }
-        }
-      }
-    }
     for (LiveInterval::Ranges::const_iterator I = cur.begin(), E = cur.end();
          I != E; ++I) {
       const LiveRange &LR = *I;
@@ -905,17 +890,6 @@ void RALinScan::assignRegOrStackSlotAtInterval(LiveInterval* cur)
     DOUT <<  tri_->getName(physReg) << '\n';
     // Note the register is not really in use.
     vrm_->assignVirt2Phys(cur->reg, physReg);
-    // Since the register allocator is allowed to assign this virtual register
-    // physical register that overlaps other live intervals. Mark these
-    // operands as "Undef" which means later passes, e.g. register scavenger
-    // can ignore them.
-    for (MachineRegisterInfo::reg_iterator RI = mri_->reg_begin(cur->reg),
-           RE = mri_->reg_end(); RI != RE; ++RI) {
-      MachineOperand &MO = RI.getOperand();
-      MO.setIsUndef();
-      if (MO.isKill())
-        MO.setIsKill(false);
-    }
     return;
   }
 
@@ -1133,8 +1107,7 @@ void RALinScan::assignRegOrStackSlotAtInterval(LiveInterval* cur)
         DowngradedRegs.clear();
         assignRegOrStackSlotAtInterval(cur);
       } else {
-        cerr << "Ran out of registers during register allocation!\n";
-        exit(1);
+        llvm_report_error("Ran out of registers during register allocation!");
       }
       return;
     }
@@ -1237,7 +1210,6 @@ void RALinScan::assignRegOrStackSlotAtInterval(LiveInterval* cur)
   // mark our rollback point.
   std::vector<LiveInterval*> added;
   while (!spillIs.empty()) {
-    bool epicFail = false;
     LiveInterval *sli = spillIs.back();
     spillIs.pop_back();
     DOUT << "\t\t\tspilling(a): " << *sli << '\n';
@@ -1254,10 +1226,6 @@ void RALinScan::assignRegOrStackSlotAtInterval(LiveInterval* cur)
     addStackInterval(sli, ls_, li_, mri_, *vrm_);
     std::copy(newIs.begin(), newIs.end(), std::back_inserter(added));
     spilled.insert(sli->reg);
-
-    if (epicFail) {
-      //abort();
-    }
   }
 
   unsigned earliestStart = earliestStartInterval->beginNumber();