Add MachineFrameInfo::getPristineRegisters(MBB) method.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78911 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineFunction.cpp b/lib/CodeGen/MachineFunction.cpp
index ab037c2..3b854a5 100644
--- a/lib/CodeGen/MachineFunction.cpp
+++ b/lib/CodeGen/MachineFunction.cpp
@@ -380,6 +380,37 @@
}
+BitVector
+MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
+ assert(MBB && "MBB must be valid");
+ const MachineFunction *MF = MBB->getParent();
+ assert(MF && "MBB must be part of a MachineFunction");
+ const TargetMachine &TM = MF->getTarget();
+ const TargetRegisterInfo *TRI = TM.getRegisterInfo();
+ BitVector BV(TRI->getNumRegs());
+
+ // Before CSI is calculated, no registers are considered pristine. They can be
+ // freely used and PEI will make sure they are saved.
+ if (!isCalleeSavedInfoValid())
+ return BV;
+
+ for (const unsigned *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
+ BV.set(*CSR);
+
+ // The entry MBB always has all CSRs pristine.
+ if (MBB == &MF->front())
+ return BV;
+
+ // On other MBBs the saved CSRs are not pristine.
+ const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
+ for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
+ E = CSI.end(); I != E; ++I)
+ BV.reset(I->getReg());
+
+ return BV;
+}
+
+
void MachineFrameInfo::print(const MachineFunction &MF, std::ostream &OS) const{
const TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
@@ -420,7 +451,6 @@
print(MF, *cerr.stream());
}
-
//===----------------------------------------------------------------------===//
// MachineJumpTableInfo implementation
//===----------------------------------------------------------------------===//