Example of code reordering from with HotSpot 20. Run on JDK6u25.

.hotspot_compiler

dontinline TestC2BranchPrediction conditionalBranch
dontinline TestC2BranchPrediction marker

.hotspotrc

+UnlockDiagnosticVMOptions
+PrintAssembly

PrintAssembly.log

Decoding compiled method 0x00007fdf4c7f29d0:
Code:
[Disassembling for mach='i386:x86-64']
[Entry Point]
[Verified Entry Point]
[Constants]
  # {method} 'conditionalBranch' '(ZZZ)V' in 'TestC2BranchPrediction'
  # parm0:    rsi       = boolean
  # parm1:    rdx       = boolean
  # parm2:    rcx       = boolean
  #           [sp+0x20]  (sp of caller)
  0x00007fdf4c7f2b40: mov    %eax,-0x6000(%rsp)
  0x00007fdf4c7f2b47: push   %rbp
  0x00007fdf4c7f2b48: sub    $0x10,%rsp         ;*synchronization entry
                                                ; - TestC2BranchPrediction::conditionalBranch@-1 (line 23)
  0x00007fdf4c7f2b4c: test   %esi,%esi
  0x00007fdf4c7f2b4e: jne    0x00007fdf4c7f2b70  ;*ifeq
                                                ; - TestC2BranchPrediction::conditionalBranch@1 (line 23)
  0x00007fdf4c7f2b50: test   %edx,%edx
  0x00007fdf4c7f2b52: je     0x00007fdf4c7f2b82  ;*ifeq
                                                ; - TestC2BranchPrediction::conditionalBranch@13 (line 25)
  0x00007fdf4c7f2b54: mov    $0x780080cd8,%rsi  ;   {oop("DO SOMETHING B")}
  0x00007fdf4c7f2b5e: nop    
  0x00007fdf4c7f2b5f: callq  0x00007fdf4c7ccc20  ; OopMap{off=36}
                                                ;*invokestatic marker
                                                ; - TestC2BranchPrediction::conditionalBranch@18 (line 26)
                                                ;   {static_call}
  0x00007fdf4c7f2b64: add    $0x10,%rsp
  0x00007fdf4c7f2b68: pop    %rbp
  0x00007fdf4c7f2b69: test   %eax,0x5687491(%rip)        # 0x00007fdf51e7a000
                                                ;   {poll_return}
  0x00007fdf4c7f2b6f: retq   
  0x00007fdf4c7f2b70: mov    $0x780080d28,%rsi  ;   {oop("DO SOMETHING A")}
  0x00007fdf4c7f2b7a: nop    
  0x00007fdf4c7f2b7b: callq  0x00007fdf4c7ccc20  ; OopMap{off=64}
                                                ;*invokestatic marker
                                                ; - TestC2BranchPrediction::conditionalBranch@6 (line 24)
                                                ;   {static_call}
  0x00007fdf4c7f2b80: jmp    0x00007fdf4c7f2b64
  0x00007fdf4c7f2b82: test   %ecx,%ecx
  0x00007fdf4c7f2b84: je     0x00007fdf4c7f2b64  ;*ifeq
                                                ; - TestC2BranchPrediction::conditionalBranch@25 (line 27)
  0x00007fdf4c7f2b86: mov    $0x780080d78,%rsi  ;   {oop("DO SOMETHING C")}
  0x00007fdf4c7f2b90: xchg   %ax,%ax
  0x00007fdf4c7f2b93: callq  0x00007fdf4c7ccc20  ; OopMap{off=88}
                                                ;*invokestatic marker
                                                ; - TestC2BranchPrediction::conditionalBranch@30 (line 28)
                                                ;   {static_call}
  0x00007fdf4c7f2b98: jmp    0x00007fdf4c7f2b64  ;*invokestatic marker
                                                ; - TestC2BranchPrediction::conditionalBranch@30 (line 28)
  0x00007fdf4c7f2b9a: mov    %rax,%rsi
  0x00007fdf4c7f2b9d: jmp    0x00007fdf4c7f2ba7  ;*invokestatic marker
                                                ; - TestC2BranchPrediction::conditionalBranch@6 (line 24)
  0x00007fdf4c7f2b9f: mov    %rax,%rsi
  0x00007fdf4c7f2ba2: jmp    0x00007fdf4c7f2ba7
  0x00007fdf4c7f2ba4: mov    %rax,%rsi          ;*invokestatic marker
                                                ; - TestC2BranchPrediction::conditionalBranch@18 (line 26)
  0x00007fdf4c7f2ba7: add    $0x10,%rsp
  0x00007fdf4c7f2bab: pop    %rbp
  0x00007fdf4c7f2bac: jmpq   0x00007fdf4c7f1e20  ;   {runtime_call}
  0x00007fdf4c7f2bb1: hlt    
  0x00007fdf4c7f2bb2: hlt    
  0x00007fdf4c7f2bb3: hlt    
  0x00007fdf4c7f2bb4: hlt    
  0x00007fdf4c7f2bb5: hlt    
  0x00007fdf4c7f2bb6: hlt    
  0x00007fdf4c7f2bb7: hlt    
  0x00007fdf4c7f2bb8: hlt    
  0x00007fdf4c7f2bb9: hlt    
  0x00007fdf4c7f2bba: hlt    
  0x00007fdf4c7f2bbb: hlt    
  0x00007fdf4c7f2bbc: hlt    
  0x00007fdf4c7f2bbd: hlt    
  0x00007fdf4c7f2bbe: hlt    
  0x00007fdf4c7f2bbf: hlt    
[Stub Code]
  0x00007fdf4c7f2bc0: mov    $0x0,%rbx          ;   {no_reloc}
  0x00007fdf4c7f2bca: jmpq   0x00007fdf4c7f2bca  ;   {runtime_call}
  0x00007fdf4c7f2bcf: mov    $0x0,%rbx          ;   {static_stub}
  0x00007fdf4c7f2bd9: jmpq   0x00007fdf4c7f2bd9  ;   {runtime_call}
  0x00007fdf4c7f2bde: mov    $0x0,%rbx          ;   {static_stub}
  0x00007fdf4c7f2be8: jmpq   0x00007fdf4c7f2be8  ;   {runtime_call}
[Exception Handler]
  0x00007fdf4c7f2bed: jmpq   0x00007fdf4c7f2620  ;   {runtime_call}
[Deopt Handler Code]
  0x00007fdf4c7f2bf2: callq  0x00007fdf4c7f2bf7
  0x00007fdf4c7f2bf7: subq   $0x5,(%rsp)
  0x00007fdf4c7f2bfc: jmpq   0x00007fdf4c7cd7c0  ;   {runtime_call}
  0x00007fdf4c7f2c01: std    
  0x00007fdf4c7f2c02: incl   (%rax)
  0x00007fdf4c7f2c04: add    %al,(%rax)
  0x00007fdf4c7f2c06: add    %al,(%rax)

TestC2BranchPrediction.java

import java.util.Random;

public class TestC2BranchPrediction {
  public static void main(String[] args) {
    Random rand = new Random();
    for (int i = 0; i < 10000000L; i++) {
      int state = rand.nextInt(10);
      switch (state) {
      case 0: case 1:
        conditionalBranch(true, true, false);
        break;
      case 2:
        conditionalBranch(false, false, true);
        break;
      default:
        conditionalBranch(false, true, false);
        break;
      }
    }
  }
  
  public static void conditionalBranch(boolean flagA, boolean flagB, boolean flagC) {
    if (flagA) {
      marker("DO SOMETHING A");
    } else if (flagB) {
      marker("DO SOMETHING B");
    } else if (flagC) {
      marker("DO SOMETHING C");
    }
  }
  
  public static void marker(String message) {
    try { message.intern(); } catch (Exception e) { }
  }
}