Reduce the offsets in DwarfDebugInfoEntry to 32 bit, they're printed with %x and

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

diff --git a/lib/CodeGen/MachineLICM.cpp b/lib/CodeGen/MachineLICM.cpp
index 8f7a8ebb264c4a24424deb06661c89c4f50559fe..e756dedff474733b44283e795d4c140fc0699c35 100644 (file)
--- a/lib/CodeGen/MachineLICM.cpp
+++ b/lib/CodeGen/MachineLICM.cpp
@@ -45,7 +45,7 @@ using namespace llvm;
 static cl::opt<bool>
 AvoidSpeculation("avoid-speculation",
                  cl::desc("MachineLICM should avoid speculation"),
-                 cl::init(false), cl::Hidden);
+                 cl::init(true), cl::Hidden);
 
 STATISTIC(NumHoisted,
           "Number of machine instructions hoisted out of loops");
@@ -762,15 +762,15 @@ void MachineLICM::UpdateRegPressure(const MachineInstr *MI) {
   }
 }
 
-/// isLoadFromGOT - Return true if this machine instruction loads from
-/// global offset table.
-static bool isLoadFromGOT(MachineInstr &MI) {
+/// isLoadFromGOTOrConstantPool - Return true if this machine instruction 
+/// loads from global offset table or constant pool.
+static bool isLoadFromGOTOrConstantPool(MachineInstr &MI) {
   assert (MI.getDesc().mayLoad() && "Expected MI that loads!");
   for (MachineInstr::mmo_iterator I = MI.memoperands_begin(),
         E = MI.memoperands_end(); I != E; ++I) {
     if (const Value *V = (*I)->getValue()) {
       if (const PseudoSourceValue *PSV = dyn_cast<PseudoSourceValue>(V))
-        if (PSV == PSV->getGOT())
+        if (PSV == PSV->getGOT() || PSV == PSV->getConstantPool())
          return true;
     }
   }
@@ -788,9 +788,11 @@ bool MachineLICM::IsLICMCandidate(MachineInstr &I) {
 
   // If it is load then check if it is guaranteed to execute by making sure that
   // it dominates all exiting blocks. If it doesn't, then there is a path out of
-  // the loop which does not execute this load, so we can't hoist it.
+  // the loop which does not execute this load, so we can't hoist it. Loads
+  // from constant memory are not safe to speculate all the time, for example
+  // indexed load from a jump table.
   // Stores and side effects are already checked by isSafeToMove.
-  if (I.getDesc().mayLoad() && !isLoadFromGOT(I) && 
+  if (I.getDesc().mayLoad() && !isLoadFromGOTOrConstantPool(I) && 
       !IsGuaranteedToExecute(I.getParent()))
     return false;
 
@@ -1196,6 +1198,7 @@ bool MachineLICM::EliminateCSE(MachineInstr *MI,
 
     // Replace virtual registers defined by MI by their counterparts defined
     // by Dup.
+    SmallVector<unsigned, 2> Defs;
     for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
       const MachineOperand &MO = MI->getOperand(i);
 
@@ -1206,11 +1209,33 @@ bool MachineLICM::EliminateCSE(MachineInstr *MI,
              "Instructions with different phys regs are not identical!");
 
       if (MO.isReg() && MO.isDef() &&
-          !TargetRegisterInfo::isPhysicalRegister(MO.getReg())) {
-        MRI->replaceRegWith(MO.getReg(), Dup->getOperand(i).getReg());
-        MRI->clearKillFlags(Dup->getOperand(i).getReg());
+          !TargetRegisterInfo::isPhysicalRegister(MO.getReg()))
+        Defs.push_back(i);
+    }
+
+    SmallVector<const TargetRegisterClass*, 2> OrigRCs;
+    for (unsigned i = 0, e = Defs.size(); i != e; ++i) {
+      unsigned Idx = Defs[i];
+      unsigned Reg = MI->getOperand(Idx).getReg();
+      unsigned DupReg = Dup->getOperand(Idx).getReg();
+      OrigRCs.push_back(MRI->getRegClass(DupReg));
+
+      if (!MRI->constrainRegClass(DupReg, MRI->getRegClass(Reg))) {
+        // Restore old RCs if more than one defs.
+        for (unsigned j = 0; j != i; ++j)
+          MRI->setRegClass(Dup->getOperand(Defs[j]).getReg(), OrigRCs[j]);
+        return false;
       }
     }
+
+    for (unsigned i = 0, e = Defs.size(); i != e; ++i) {
+      unsigned Idx = Defs[i];
+      unsigned Reg = MI->getOperand(Idx).getReg();
+      unsigned DupReg = Dup->getOperand(Idx).getReg();
+      MRI->replaceRegWith(Reg, DupReg);
+      MRI->clearKillFlags(DupReg);
+    }
+
     MI->eraseFromParent();
     ++NumCSEed;
     return true;