X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=blobdiff_plain;f=lib%2FTarget%2FAArch64%2FAArch64FrameLowering.cpp;h=3f63d049c34ed109fb8007a1103ef8bac6a2e294;hp=11ae8005370d10326afb44f7e2d734ec8a2a74fe;hb=bb6f14e3581c78509405a3d415e72821db8a2066;hpb=e970b795a27d16c720bf4e3ff030eea241784eb4;ds=sidebyside

diff --git a/lib/Target/AArch64/AArch64FrameLowering.cpp b/lib/Target/AArch64/AArch64FrameLowering.cpp
index 11ae8005370..3f63d049c34 100644
--- a/lib/Target/AArch64/AArch64FrameLowering.cpp
+++ b/lib/Target/AArch64/AArch64FrameLowering.cpp
@@ -275,6 +275,18 @@ static bool isCSSave(MachineInstr *MBBI) {
          MBBI->getOpcode() == AArch64::STPDpre;
 }
 
+bool AArch64FrameLowering::canUseAsPrologue(
+    const MachineBasicBlock &MBB) const {
+  const MachineFunction *MF = MBB.getParent();
+  const AArch64Subtarget &Subtarget = MF->getSubtarget<AArch64Subtarget>();
+  const AArch64RegisterInfo *RegInfo = Subtarget.getRegisterInfo();
+
+  // Don't need a scratch register if we're not going to re-align the stack.
+  // Otherwise, we may need a scratch register to be available and we do not
+  // support that for now.
+  return !RegInfo->needsStackRealignment(*MF);
+}
+
 void AArch64FrameLowering::emitPrologue(MachineFunction &MF,
                                         MachineBasicBlock &MBB) const {
   MachineBasicBlock::iterator MBBI = MBB.begin();