The last verification check for the new EH model.

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

diff --git a/lib/CodeGen/InlineSpiller.cpp b/lib/CodeGen/InlineSpiller.cpp
index 169a867aa7a5500eabc2eeb1936fc5c1b657c947..b63611b94c1c1d403d38d9160a6dac9fe77d837e 100644 (file)
--- a/lib/CodeGen/InlineSpiller.cpp
+++ b/lib/CodeGen/InlineSpiller.cpp
@@ -28,6 +28,7 @@
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 
@@ -45,6 +46,9 @@ STATISTIC(NumRemats,          "Number of rematerialized defs for spilling");
 STATISTIC(NumOmitReloadSpill, "Number of omitted spills of reloads");
 STATISTIC(NumHoists,          "Number of hoisted spills");
 
+static cl::opt<bool> DisableHoisting("disable-spill-hoist", cl::Hidden,
+                                     cl::desc("Disable inline spill hoisting"));
+
 namespace {
 class InlineSpiller : public Spiller {
   MachineFunctionPass &Pass;
@@ -86,6 +90,9 @@ public:
     // True when value is defined by an original PHI not from splitting.
     bool DefByOrigPHI;
 
+    // True when the COPY defining this value killed its source.
+    bool KillsSource;
+
     // The preferred register to spill.
     unsigned SpillReg;
 
@@ -108,7 +115,7 @@ public:
     TinyPtrVector<VNInfo*> Deps;
 
     SibValueInfo(unsigned Reg, VNInfo *VNI)
-      : AllDefsAreReloads(true), DefByOrigPHI(false),
+      : AllDefsAreReloads(true), DefByOrigPHI(false), KillsSource(false),
         SpillReg(Reg), SpillVNI(VNI), SpillMBB(0), DefMI(0) {}
 
     // Returns true when a def has been found.
@@ -315,6 +322,8 @@ static raw_ostream &operator<<(raw_ostream &OS,
     OS << " all-reloads";
   if (SVI.DefByOrigPHI)
     OS << " orig-phi";
+  if (SVI.KillsSource)
+    OS << " kill";
   OS << " deps[";
   for (unsigned i = 0, e = SVI.Deps.size(); i != e; ++i)
     OS << ' ' << SVI.Deps[i]->id << '@' << SVI.Deps[i]->def;
@@ -367,7 +376,7 @@ void InlineSpiller::propagateSiblingValue(SibValueMap::iterator SVI,
 
     // Should this value be propagated as a preferred spill candidate?  We don't
     // propagate values of registers that are about to spill.
-    bool PropSpill = !isRegToSpill(SV.SpillReg);
+    bool PropSpill = !DisableHoisting && !isRegToSpill(SV.SpillReg);
     unsigned SpillDepth = ~0u;
 
     for (TinyPtrVector<VNInfo*>::iterator DepI = Deps->begin(),
@@ -398,7 +407,7 @@ void InlineSpiller::propagateSiblingValue(SibValueMap::iterator SVI,
       if (PropSpill && SV.SpillVNI != DepSV.SpillVNI) {
         if (SV.SpillMBB == DepSV.SpillMBB) {
           // DepSV is in the same block.  Hoist when dominated.
-          if (SV.SpillVNI->def < DepSV.SpillVNI->def) {
+          if (DepSV.KillsSource && SV.SpillVNI->def < DepSV.SpillVNI->def) {
             // This is an alternative def earlier in the same MBB.
             // Hoist the spill as far as possible in SpillMBB. This can ease
             // register pressure:
@@ -414,6 +423,7 @@ void InlineSpiller::propagateSiblingValue(SibValueMap::iterator SVI,
             //   spill x
             //   y = use x<kill>
             //
+            // This hoist only helps when the DepSV copy kills its source.
             Changed = true;
             DepSV.SpillReg = SV.SpillReg;
             DepSV.SpillVNI = SV.SpillVNI;
@@ -568,10 +578,14 @@ MachineInstr *InlineSpiller::traceSiblingValue(unsigned UseReg, VNInfo *UseVNI,
     if (unsigned SrcReg = isFullCopyOf(MI, Reg)) {
       if (isSibling(SrcReg)) {
         LiveInterval &SrcLI = LIS.getInterval(SrcReg);
-        VNInfo *SrcVNI = SrcLI.getVNInfoAt(VNI->def.getUseIndex());
-        assert(SrcVNI && "Copy from non-existing value");
+        LiveRange *SrcLR = SrcLI.getLiveRangeContaining(VNI->def.getUseIndex());
+        assert(SrcLR && "Copy from non-existing value");
+        // Check if this COPY kills its source.
+        SVI->second.KillsSource = (SrcLR->end == VNI->def);
+        VNInfo *SrcVNI = SrcLR->valno;
         DEBUG(dbgs() << "copy of " << PrintReg(SrcReg) << ':'
-                     << SrcVNI->id << '@' << SrcVNI->def << '\n');
+                     << SrcVNI->id << '@' << SrcVNI->def
+                     << " kill=" << unsigned(SVI->second.KillsSource) << '\n');
         // Known sibling source value? Try an insertion.
         tie(SVI, Inserted) = SibValues.insert(std::make_pair(SrcVNI,
                                                  SibValueInfo(SrcReg, SrcVNI)));