1 files changed, 13 insertions, 3 deletions
diff --git a/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp b/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
index 21b8e6b8705..4c69a90c4b6 100644
--- a/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
+++ b/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
@@ -1866,6 +1866,15 @@ void llvm::emitARMRegPlusImmediate(MachineBasicBlock &MBB,
   }
 }
 
+static bool isAnySubRegLive(unsigned Reg, const TargetRegisterInfo *TRI,
+                      MachineInstr *MI) {
+  for (MCSubRegIterator Subreg(Reg, TRI, /* IncludeSelf */ true);
+       Subreg.isValid(); ++Subreg)
+    if (MI->getParent()->computeRegisterLiveness(TRI, *Subreg, MI) !=
+        MachineBasicBlock::LQR_Dead)
+      return true;
+  return false;
+}
 bool llvm::tryFoldSPUpdateIntoPushPop(const ARMSubtarget &Subtarget,
                                       MachineFunction &MF, MachineInstr *MI,
                                       unsigned NumBytes) {
@@ -1920,7 +1929,6 @@ bool llvm::tryFoldSPUpdateIntoPushPop(const ARMSubtarget &Subtarget,
   for (int i = MI->getNumOperands() - 1; i >= RegListIdx; --i)
     RegList.push_back(MI->getOperand(i));
 
-  MachineBasicBlock *MBB = MI->getParent();
   const TargetRegisterInfo *TRI = MF.getRegInfo().getTargetRegisterInfo();
   const MCPhysReg *CSRegs = TRI->getCalleeSavedRegs(&MF);
 
@@ -1941,9 +1949,11 @@ bool llvm::tryFoldSPUpdateIntoPushPop(const ARMSubtarget &Subtarget,
     // registers live within the function we might clobber a return value
     // register; the other way a register can be live here is if it's
     // callee-saved.
+    // TODO: Currently, computeRegisterLiveness() does not report "live" if a
+    // sub reg is live. When computeRegisterLiveness() works for sub reg, it
+    // can replace isAnySubRegLive().
     if (isCalleeSavedRegister(CurReg, CSRegs) ||
-        MBB->computeRegisterLiveness(TRI, CurReg, MI) !=
-            MachineBasicBlock::LQR_Dead) {
+        isAnySubRegLive(CurReg, TRI, MI)) {
       // VFP pops don't allow holes in the register list, so any skip is fatal
       // for our transformation. GPR pops do, so we should just keep looking.
       if (IsVFPPushPop)