diff --git a/llvm/lib/Target/BPF/BPFMIPeephole.cpp b/llvm/lib/Target/BPF/BPFMIPeephole.cpp
--- a/llvm/lib/Target/BPF/BPFMIPeephole.cpp
+++ b/llvm/lib/Target/BPF/BPFMIPeephole.cpp
@@ -57,6 +57,7 @@
   bool isPhiFrom32Def(MachineInstr *MovMI);
   bool isMovFrom32Def(MachineInstr *MovMI);
   bool eliminateZExtSeq(void);
+  bool eliminateZExt(void);
 
   std::set<MachineInstr *> PhiInsns;
 
@@ -69,7 +70,12 @@
 
     initialize(MF);
 
-    return eliminateZExtSeq();
+    // First try to eliminate (zext, lshift, rshift) and then
+    // try to eliminate zext.
+    bool ZExtSeqExist, ZExtExist;
+    ZExtSeqExist = eliminateZExtSeq();
+    ZExtExist = eliminateZExt();
+    return ZExtSeqExist || ZExtExist;
   }
 };
 
@@ -234,6 +240,51 @@
   return Eliminated;
 }
 
+bool BPFMIPeephole::eliminateZExt(void) {
+  MachineInstr* ToErase = nullptr;
+  bool Eliminated = false;
+
+  for (MachineBasicBlock &MBB : *MF) {
+    for (MachineInstr &MI : MBB) {
+      // If the previous instruction was marked for elimination, remove it now.
+      if (ToErase) {
+        ToErase->eraseFromParent();
+        ToErase = nullptr;
+      }
+
+      if (MI.getOpcode() != BPF::MOV_32_64)
+        continue;
+
+      // Eliminate MOV_32_64 if possible.
+      //   MOV_32_64 rA, wB
+      //
+      // If wB has been zero extended, replace it with a SUBREG_TO_REG.
+      // This is to workaround BPF programs where pkt->{data, data_end}
+      // is encoded as u32, but actually the verifier populates them
+      // as 64bit pointer. The MOV_32_64 will zero out the top 32 bits.
+      LLVM_DEBUG(dbgs() << "Candidate MOV_32_64 instruction:");
+      LLVM_DEBUG(MI.dump());
+
+      if (!isMovFrom32Def(&MI))
+        continue;
+
+      LLVM_DEBUG(dbgs() << "Removing the MOV_32_64 instruction\n");
+
+      Register dst = MI.getOperand(0).getReg();
+      Register src = MI.getOperand(1).getReg();
+
+      // Build a SUBREG_TO_REG instruction.
+      BuildMI(MBB, MI, MI.getDebugLoc(), TII->get(BPF::SUBREG_TO_REG), dst)
+        .addImm(0).addReg(src).addImm(BPF::sub_32);
+
+      ToErase = &MI;
+      Eliminated = true;
+    }
+  }
+
+  return Eliminated;
+}
+
 } // end default namespace
 
 INITIALIZE_PASS(BPFMIPeephole, DEBUG_TYPE,
diff --git a/llvm/test/CodeGen/BPF/remove_truncate_7.ll b/llvm/test/CodeGen/BPF/remove_truncate_7.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/BPF/remove_truncate_7.ll
@@ -0,0 +1,55 @@
+; RUN: llc < %s -march=bpf -mattr=+alu32 -verify-machineinstrs | FileCheck %s
+;
+; Source:
+;  struct __sk_buff {
+;    unsigned data;
+;    unsigned data_end;
+;  };
+;
+;  void * test(int flag, struct __sk_buff *skb)
+;  {
+;    void *p;
+;
+;    if (flag) {
+;      p = (void *)(long)skb->data;
+;      __asm__ __volatile__("": : :"memory");
+;    } else {
+;      p = (void *)(long)skb->data_end;
+;      __asm__ __volatile__("": : :"memory");
+;    }
+;
+;    return p;
+;  }
+; Compilation flag:
+;   clang -target bpf -O2 -S -emit-llvm t.c
+
+%struct.__sk_buff = type { i32, i32 }
+
+define dso_local i8* @test(i32 %flag, %struct.__sk_buff* nocapture readonly %skb) local_unnamed_addr {
+entry:
+  %tobool = icmp eq i32 %flag, 0
+  br i1 %tobool, label %if.else, label %if.then
+
+if.then:
+  %data = getelementptr inbounds %struct.__sk_buff, %struct.__sk_buff* %skb, i64 0, i32 0
+  %0 = load i32, i32* %data, align 4
+  tail call void asm sideeffect "", "~{memory}"()
+  br label %if.end
+
+if.else:
+  %data_end = getelementptr inbounds %struct.__sk_buff, %struct.__sk_buff* %skb, i64 0, i32 1
+  %1 = load i32, i32* %data_end, align 4
+  tail call void asm sideeffect "", "~{memory}"()
+  br label %if.end
+
+if.end:
+  %p.0.in.in = phi i32 [ %0, %if.then ], [ %1, %if.else ]
+  %p.0.in = zext i32 %p.0.in.in to i64
+  %p.0 = inttoptr i64 %p.0.in to i8*
+  ret i8* %p.0
+}
+
+; CHECK:       w0 = *(u32 *)(r2 + 0)
+; CHECK:       w0 = *(u32 *)(r2 + 4)
+; CHECK-NOT:   r[[#]] = w[[#]]
+; CHECK:       exit