diff --git a/llvm/lib/Target/AVR/AVR.h b/llvm/lib/Target/AVR/AVR.h
--- a/llvm/lib/Target/AVR/AVR.h
+++ b/llvm/lib/Target/AVR/AVR.h
@@ -28,7 +28,6 @@
 FunctionPass *createAVRExpandPseudoPass();
 FunctionPass *createAVRFrameAnalyzerPass();
 FunctionPass *createAVRRelaxMemPass();
-FunctionPass *createAVRDynAllocaSRPass();
 FunctionPass *createAVRBranchSelectionPass();
 
 void initializeAVRShiftExpandPass(PassRegistry &);
diff --git a/llvm/lib/Target/AVR/AVRFrameLowering.cpp b/llvm/lib/Target/AVR/AVRFrameLowering.cpp
--- a/llvm/lib/Target/AVR/AVRFrameLowering.cpp
+++ b/llvm/lib/Target/AVR/AVRFrameLowering.cpp
@@ -176,7 +176,7 @@
   const AVRInstrInfo &TII = *STI.getInstrInfo();
 
   // Early exit if there is no need to restore the frame pointer.
-  if (!FrameSize) {
+  if (!FrameSize && !MF.getFrameInfo().hasVarSizedObjects()) {
     restoreStatusRegister(MF, MBB);
     return;
   }
@@ -193,22 +193,24 @@
     --MBBI;
   }
 
-  unsigned Opcode;
+  if (FrameSize) {
+    unsigned Opcode;
 
-  // Select the optimal opcode depending on how big it is.
-  if (isUInt<6>(FrameSize)) {
-    Opcode = AVR::ADIWRdK;
-  } else {
-    Opcode = AVR::SUBIWRdK;
-    FrameSize = -FrameSize;
-  }
+    // Select the optimal opcode depending on how big it is.
+    if (isUInt<6>(FrameSize)) {
+      Opcode = AVR::ADIWRdK;
+    } else {
+      Opcode = AVR::SUBIWRdK;
+      FrameSize = -FrameSize;
+    }
 
-  // Restore the frame pointer by doing FP += <size>.
-  MachineInstr *MI = BuildMI(MBB, MBBI, DL, TII.get(Opcode), AVR::R29R28)
-                         .addReg(AVR::R29R28, RegState::Kill)
-                         .addImm(FrameSize);
-  // The SREG implicit def is dead.
-  MI->getOperand(3).setIsDead();
+    // Restore the frame pointer by doing FP += <size>.
+    MachineInstr *MI = BuildMI(MBB, MBBI, DL, TII.get(Opcode), AVR::R29R28)
+                          .addReg(AVR::R29R28, RegState::Kill)
+                          .addImm(FrameSize);
+    // The SREG implicit def is dead.
+    MI->getOperand(3).setIsDead();
+  }
 
   // Write back R29R28 to SP and temporarily disable interrupts.
   BuildMI(MBB, MBBI, DL, TII.get(AVR::SPWRITE), AVR::SP)
@@ -230,7 +232,8 @@
   const AVRMachineFunctionInfo *FuncInfo = MF.getInfo<AVRMachineFunctionInfo>();
 
   return (FuncInfo->getHasSpills() || FuncInfo->getHasAllocas() ||
-          FuncInfo->getHasStackArgs());
+          FuncInfo->getHasStackArgs() ||
+          MF.getFrameInfo().hasVarSizedObjects());
 }
 
 bool AVRFrameLowering::spillCalleeSavedRegisters(
@@ -480,56 +483,4 @@
 /// Creates instance of the frame analyzer pass.
 FunctionPass *createAVRFrameAnalyzerPass() { return new AVRFrameAnalyzer(); }
 
-/// Create the Dynalloca Stack Pointer Save/Restore pass.
-/// Insert a copy of SP before allocating the dynamic stack memory and restore
-/// it in function exit to restore the original SP state. This avoids the need
-/// of reserving a register pair for a frame pointer.
-struct AVRDynAllocaSR : public MachineFunctionPass {
-  static char ID;
-  AVRDynAllocaSR() : MachineFunctionPass(ID) {}
-
-  bool runOnMachineFunction(MachineFunction &MF) override {
-    // Early exit when there are no variable sized objects in the function.
-    if (!MF.getFrameInfo().hasVarSizedObjects()) {
-      return false;
-    }
-
-    const AVRSubtarget &STI = MF.getSubtarget<AVRSubtarget>();
-    const TargetInstrInfo &TII = *STI.getInstrInfo();
-    MachineBasicBlock &EntryMBB = MF.front();
-    MachineBasicBlock::iterator MBBI = EntryMBB.begin();
-    DebugLoc DL = EntryMBB.findDebugLoc(MBBI);
-
-    Register SPCopy =
-        MF.getRegInfo().createVirtualRegister(&AVR::DREGSRegClass);
-
-    // Create a copy of SP in function entry before any dynallocas are
-    // inserted.
-    BuildMI(EntryMBB, MBBI, DL, TII.get(AVR::COPY), SPCopy).addReg(AVR::SP);
-
-    // Restore SP in all exit basic blocks.
-    for (MachineBasicBlock &MBB : MF) {
-      // If last instruction is a return instruction, add a restore copy.
-      if (!MBB.empty() && MBB.back().isReturn()) {
-        MBBI = MBB.getLastNonDebugInstr();
-        DL = MBBI->getDebugLoc();
-        BuildMI(MBB, MBBI, DL, TII.get(AVR::COPY), AVR::SP)
-            .addReg(SPCopy, RegState::Kill);
-      }
-    }
-
-    return true;
-  }
-
-  StringRef getPassName() const override {
-    return "AVR dynalloca stack pointer save/restore";
-  }
-};
-
-char AVRDynAllocaSR::ID = 0;
-
-/// createAVRDynAllocaSRPass - returns an instance of the dynalloca stack
-/// pointer save/restore pass.
-FunctionPass *createAVRDynAllocaSRPass() { return new AVRDynAllocaSR(); }
-
 } // end of namespace llvm
diff --git a/llvm/lib/Target/AVR/AVRTargetMachine.cpp b/llvm/lib/Target/AVR/AVRTargetMachine.cpp
--- a/llvm/lib/Target/AVR/AVRTargetMachine.cpp
+++ b/llvm/lib/Target/AVR/AVRTargetMachine.cpp
@@ -70,7 +70,6 @@
   bool addInstSelector() override;
   void addPreSched2() override;
   void addPreEmitPass() override;
-  void addPreRegAlloc() override;
 };
 } // namespace
 
@@ -118,11 +117,6 @@
   return false;
 }
 
-void AVRPassConfig::addPreRegAlloc() {
-  // Create the dynalloc SP save/restore pass to handle variable sized allocas.
-  addPass(createAVRDynAllocaSRPass());
-}
-
 void AVRPassConfig::addPreSched2() {
   addPass(createAVRRelaxMemPass());
   addPass(createAVRExpandPseudoPass());
diff --git a/llvm/test/CodeGen/AVR/dynalloca.ll b/llvm/test/CodeGen/AVR/dynalloca.ll
--- a/llvm/test/CodeGen/AVR/dynalloca.ll
+++ b/llvm/test/CodeGen/AVR/dynalloca.ll
@@ -4,10 +4,10 @@
 
 define void @test1(i16 %x) {
 ; CHECK-LABEL: test1:
+; Frame setup, with frame pointer
+; CHECK: in r28, 61
+; CHECK: in r29, 62
 ; CHECK: out 61, r28
-; SP copy
-; CHECK-NEXT: in [[SPCOPY1:r[0-9]+]], 61
-; CHECK-NEXT: in [[SPCOPY2:r[0-9]+]], 62
 ; allocate first dynalloca
 ; CHECK: in {{.*}}, 61
 ; CHECK: in {{.*}}, 62
@@ -26,9 +26,9 @@
 ; Test SP restore
 ; CHECK: in r0, 63
 ; CHECK-NEXT: cli
-; CHECK-NEXT: out 62, [[SPCOPY2]]
+; CHECK-NEXT: out 62, r29
 ; CHECK-NEXT: out 63, r0
-; CHECK-NEXT: out 61, [[SPCOPY1]]
+; CHECK-NEXT: out 61, r28
   %a = alloca [8 x i16]
   %vla = alloca i16, i16 %x
   %add = shl nsw i16 %x, 1
@@ -51,8 +51,8 @@
 ; after the call frame is restored and not before.
 define void @dynalloca2(i16 %x) {
 ; CHECK-LABEL: dynalloca2:
-; CHECK: in [[SPCOPY1:r[0-9]+]], 61
-; CHECK: in [[SPCOPY2:r[0-9]+]], 62
+; CHECK: in r28, 61
+; CHECK: in r29, 62
 ; Allocate stack space for call
 ; CHECK: in {{.*}}, 61
 ; CHECK: in {{.*}}, 62
@@ -87,10 +87,40 @@
 ; SP restore
 ; CHECK: in r0, 63
 ; CHECK-NEXT: cli
-; CHECK-NEXT: out 62, r7
+; CHECK-NEXT: out 62, r29
 ; CHECK-NEXT: out 63, r0
-; CHECK-NEXT: out 61, r6
+; CHECK-NEXT: out 61, r28
   %vla = alloca i16, i16 %x
   call void @foo2(i16* %vla, i64 0, i64 0, i64 0)
   ret void
 }
+
+; Test a function with a variable sized object but without any other need for a
+; frame pointer.
+; Allocas that are not placed in the entry block are considered variable sized
+; (they could be in a loop).
+define void @dynalloca3() {
+; CHECK-LABEL: dynalloca3:
+; Read frame pointer
+; CHECK:      in r28, 61
+; CHECK-NEXT: in r29, 62
+; Allocate memory for the alloca
+; CHECK-NEXT: in r24, 61
+; CHECK-NEXT: in r25, 62
+; CHECK-NEXT: sbiw r24, 8
+; CHECK-NEXT: in r0, 63
+; CHECK-NEXT: cli
+; CHECK-NEXT: out 62, r25
+; CHECK-NEXT: out 63, r0
+; CHECK-NEXT: out 61, r24
+; Restore frame pointer
+; CHECK-NEXT: in r0, 63
+; CHECK-NEXT: cli
+; CHECK-NEXT: out 62, r29
+; CHECK-NEXT: out 63, r0
+; CHECK-NEXT: out 61, r28
+  br label %1
+1:
+  %a = alloca i64
+  ret void
+}