Move CalculateRegClass to MRI::recomputeRegClass.

This function doesn't have anything to do with spill weights, and MRI
already has functions for manipulating the register class of a virtual
register.

llvm-svn: 137123

include/llvm/CodeGen/CalcSpillWeights.h

@@ -49,11 +49,6 @@ namespace llvm {
                    const MachineLoopInfo &loops) :
       MF(mf), LIS(lis), Loops(loops) {}
 
-    /// CalculateRegClass - recompute the register class for reg from its uses.
-    /// Since the register class can affect the allocation hint, this function
-    /// should be called before CalculateWeightAndHint if both are called.
-    void CalculateRegClass(unsigned reg);
-
     /// CalculateWeightAndHint - (re)compute li's spill weight and allocation
     /// hint.
     void CalculateWeightAndHint(LiveInterval &li);

include/llvm/CodeGen/MachineRegisterInfo.h

@@ -219,9 +219,20 @@ public:
   /// Return the new register class, or NULL if no such class exists.
   /// This should only be used when the constraint is known to be trivial, like
   /// GR32 -> GR32_NOSP. Beware of increasing register pressure.
+  ///
   const TargetRegisterClass *constrainRegClass(unsigned Reg,
                                                const TargetRegisterClass *RC);
 
+  /// recomputeRegClass - Try to find a legal super-class of Reg's register
+  /// class that still satisfies the constraints from the instructions using
+  /// Reg.  Returns true if Reg was upgraded.
+  ///
+  /// This method can be used after constraints have been removed from a
+  /// virtual register, for example after removing instructions or splitting
+  /// the live range.
+  ///
+  bool recomputeRegClass(unsigned Reg, const TargetMachine&);
+
   /// createVirtualRegister - Create and return a new virtual register in the
   /// function with the specified register class.
   ///

lib/CodeGen/CalcSpillWeights.cpp

@@ -185,35 +185,3 @@ void VirtRegAuxInfo::CalculateWeightAndHint(LiveInterval &li) {
 
   li.weight = normalizeSpillWeight(totalWeight, li.getSize());
 }
-
-void VirtRegAuxInfo::CalculateRegClass(unsigned reg) {
-  MachineRegisterInfo &MRI = MF.getRegInfo();
-  const TargetInstrInfo *TII = MF.getTarget().getInstrInfo();
-  const TargetRegisterInfo *TRI = MF.getTarget().getRegisterInfo();
-  const TargetRegisterClass *OldRC = MRI.getRegClass(reg);
-  const TargetRegisterClass *NewRC = TRI->getLargestLegalSuperClass(OldRC);
-
-  // Stop early if there is no room to grow.
-  if (NewRC == OldRC)
-    return;
-
-  // Accumulate constraints from all uses.
-  for (MachineRegisterInfo::reg_nodbg_iterator I = MRI.reg_nodbg_begin(reg),
-       E = MRI.reg_nodbg_end(); I != E; ++I) {
-    // TRI doesn't have accurate enough information to model this yet.
-    if (I.getOperand().getSubReg())
-      return;
-    // Inline asm instuctions don't remember their constraints.
-    if (I->isInlineAsm())
-      return;
-    const TargetRegisterClass *OpRC =
-      TII->getRegClass(I->getDesc(), I.getOperandNo(), TRI);
-    if (OpRC)
-      NewRC = getCommonSubClass(NewRC, OpRC);
-    if (!NewRC || NewRC == OldRC)
-      return;
-  }
-  DEBUG(dbgs() << "Inflating " << OldRC->getName() << ':' << PrintReg(reg)
-               << " to " << NewRC->getName() <<".\n");
-  MRI.setRegClass(reg, NewRC);
-}

lib/CodeGen/LiveRangeEdit.cpp

@@ -319,9 +319,12 @@ void LiveRangeEdit::calculateRegClassAndHint(MachineFunction &MF,
                                              LiveIntervals &LIS,
                                              const MachineLoopInfo &Loops) {
   VirtRegAuxInfo VRAI(MF, LIS, Loops);
+  MachineRegisterInfo &MRI = MF.getRegInfo();
   for (iterator I = begin(), E = end(); I != E; ++I) {
     LiveInterval &LI = **I;
-    VRAI.CalculateRegClass(LI.reg);
+    if (MRI.recomputeRegClass(LI.reg, MF.getTarget()))
+      DEBUG(dbgs() << "Inflated " << PrintReg(LI.reg) << " to "
+                   << MRI.getRegClass(LI.reg)->getName() << '\n');
     VRAI.CalculateWeightAndHint(LI);
   }
 }

lib/CodeGen/MachineRegisterInfo.cpp

@@ -14,7 +14,7 @@
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/Target/TargetInstrInfo.h"
-#include "llvm/Support/CommandLine.h"
+#include "llvm/Target/TargetMachine.h"
 using namespace llvm;
 
 MachineRegisterInfo::MachineRegisterInfo(const TargetRegisterInfo &TRI)
@@ -61,6 +61,37 @@ MachineRegisterInfo::constrainRegClass(unsigned Reg,
   return NewRC;
 }
 
+bool
+MachineRegisterInfo::recomputeRegClass(unsigned Reg, const TargetMachine &TM) {
+  const TargetInstrInfo *TII = TM.getInstrInfo();
+  const TargetRegisterInfo *TRI = TM.getRegisterInfo();
+  const TargetRegisterClass *OldRC = getRegClass(Reg);
+  const TargetRegisterClass *NewRC = TRI->getLargestLegalSuperClass(OldRC);
+
+  // Stop early if there is no room to grow.
+  if (NewRC == OldRC)
+    return false;
+
+  // Accumulate constraints from all uses.
+  for (reg_nodbg_iterator I = reg_nodbg_begin(Reg), E = reg_nodbg_end(); I != E;
+       ++I) {
+    // TRI doesn't have accurate enough information to model this yet.
+    if (I.getOperand().getSubReg())
+      return false;
+    // Inline asm instuctions don't remember their constraints.
+    if (I->isInlineAsm())
+      return false;
+    const TargetRegisterClass *OpRC =
+      TII->getRegClass(I->getDesc(), I.getOperandNo(), TRI);
+    if (OpRC)
+      NewRC = getCommonSubClass(NewRC, OpRC);
+    if (!NewRC || NewRC == OldRC)
+      return false;
+  }
+  setRegClass(Reg, NewRC);
+  return true;
+}
+
 /// createVirtualRegister - Create and return a new virtual register in the
 /// function with the specified register class.
 ///