LivePhysRegs: addLiveOuts() can skip addPristines() in ret block

Drive-by improvement: We would 1) add CSRs, 2) remove callee saved CSRs
and 3) add all CSRs again for the return block.  Just adding CSRs once
obviously gives the same results.

llvm-svn: 274955

diff --git a/llvm/lib/CodeGen/LivePhysRegs.cpp b/llvm/lib/CodeGen/LivePhysRegs.cpp
index 57faef3..4e2528f 100644 (file)
--- a/llvm/lib/CodeGen/LivePhysRegs.cpp
+++ b/llvm/lib/CodeGen/LivePhysRegs.cpp
@@ -167,12 +167,13 @@ void LivePhysRegs::addLiveOuts(const MachineBasicBlock &MBB) {
   const MachineFunction &MF = *MBB.getParent();
   const MachineFrameInfo &MFI = *MF.getFrameInfo();
   if (MFI.isCalleeSavedInfoValid()) {
-    addPristines(*this, MF, MFI, *TRI);
     if (MBB.isReturnBlock()) {
       // The return block has no successors whose live-ins we could merge
       // below. So instead we add the callee saved registers manually.
       for (const MCPhysReg *I = TRI->getCalleeSavedRegs(&MF); *I; ++I)
         addReg(*I);
+    } else {
+      addPristines(*this, MF, MFI, *TRI);
     }
   }