Add a convenient PSetIterator for visiting pressure sets affected by a register.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189121 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 46 insertions, 0 deletions

diff --git a/include/llvm/CodeGen/MachineRegisterInfo.h b/include/llvm/CodeGen/MachineRegisterInfo.h
index 4fb1ac9..736a0a2 100644
--- a/include/llvm/CodeGen/MachineRegisterInfo.h
+++ b/include/llvm/CodeGen/MachineRegisterInfo.h
@@ -22,6 +22,7 @@
 #include <vector>
 
 namespace llvm {
+class PSetIterator;
 
 /// MachineRegisterInfo - Keep track of information for virtual and physical
 /// registers, including vreg register classes, use/def chains for registers,
@@ -326,6 +327,11 @@ public:
   /// a physreg.
   bool isConstantPhysReg(unsigned PhysReg, const MachineFunction &MF) const;
 
+  /// Get an iterator over the pressure sets affected by the given physical or
+  /// virtual register. If RegUnit is physical, it must be a register unit (from
+  /// MCRegUnitIterator).
+  PSetIterator getPressureSets(unsigned RegUnit) const;
+
   //===--------------------------------------------------------------------===//
   // Virtual Register Info
   //===--------------------------------------------------------------------===//
@@ -647,9 +653,49 @@ public:
       return Op->getParent();
     }
   };
+};
 
+/// Iterate over the pressure sets affected by the given physical or virtual
+/// register. If Reg is physical, it must be a register unit (from
+/// MCRegUnitIterator).
+class PSetIterator {
+  const int *PSet;
+  unsigned Weight;
+public:
+  PSetIterator(): PSet(0), Weight(0) {}
+  PSetIterator(unsigned RegUnit, const MachineRegisterInfo *MRI) {
+    const TargetRegisterInfo *TRI = MRI->getTargetRegisterInfo();
+    if (TargetRegisterInfo::isVirtualRegister(RegUnit)) {
+      const TargetRegisterClass *RC = MRI->getRegClass(RegUnit);
+      PSet = TRI->getRegClassPressureSets(RC);
+      Weight = TRI->getRegClassWeight(RC).RegWeight;
+    }
+    else {
+      PSet = TRI->getRegUnitPressureSets(RegUnit);
+      Weight = TRI->getRegUnitWeight(RegUnit);
+    }
+    if (*PSet == -1)
+      PSet = 0;
+  }
+  bool isValid() const { return PSet; }
+
+  unsigned getWeight() const { return Weight; }
+
+  unsigned operator*() const { return *PSet; }
+
+  void operator++() {
+    assert(isValid() && "Invalid PSetIterator.");
+    ++PSet;
+    if (*PSet == -1)
+      PSet = 0;
+  }
 };
 
+inline PSetIterator MachineRegisterInfo::
+getPressureSets(unsigned RegUnit) const {
+  return PSetIterator(RegUnit, this);
+}
+
 } // End llvm namespace
 
 #endif