Program: 149948
Project: 149948
Buggy source:
/** 
 * prologue for the exceptional case. (1) R0 is the only available scratch register. (2) stack overflow check has to come first.
 */
final void insertExceptionalPrologue(){
  if (frameSize >= 0x7ff0) {
    throw new OPT_OptimizingCompilerException("String_Node_Str");
  }
  OPT_PhysicalRegisterSet phys=ir.regpool.getPhysicalRegisterSet();
  OPT_Register FP=phys.getFP();
  OPT_Register PR=phys.getPR();
  OPT_Register TSR=phys.getTSR();
  OPT_Register R0=phys.getTemp();
  OPT_Register S1=phys.getGPR(LAST_SCRATCH_GPR);
  boolean interruptible=ir.method.isInterruptible();
  boolean stackOverflow=interruptible;
  boolean yp=hasPrologueYieldpoint();
  OPT_Instruction ptr=ir.firstInstructionInCodeOrder().nextInstructionInCodeOrder();
  if (VM.VerifyAssertions)   VM._assert(ptr.getOpcode() == IR_PROLOGUE_opcode);
  if (stackOverflow) {
    ptr.insertBefore(MIR_Store.create(PPC_STAddr,A(S1),A(FP),IC(STACKFRAME_NEXT_INSTRUCTION_OFFSET)));
    Offset offset=VM_Entrypoints.activeThreadStackLimitField.getOffset();
    if (VM.VerifyAssertions)     VM._assert(OPT_Bits.fits(offset,16));
    ptr.insertBefore(MIR_Load.create(PPC_LAddr,A(S1),A(phys.getPR()),IC(OPT_Bits.PPCMaskLower16(offset))));
    ptr.insertBefore(MIR_Binary.create(PPC_ADDI,A(R0),A(S1),IC(frameSize)));
    ptr.insertBefore(MIR_Load.create(PPC_LAddr,A(S1),A(FP),IC(STACKFRAME_NEXT_INSTRUCTION_OFFSET)));
    MIR_Trap.mutate(ptr,PPC_TAddr,OPT_PowerPCTrapOperand.LESS(),A(FP),A(R0),OPT_TrapCodeOperand.StackOverflow());
    ptr=ptr.nextInstructionInCodeOrder();
  }
 else {
    OPT_Instruction next=ptr.nextInstructionInCodeOrder();
    ptr.remove();
    ptr=next;
  }
  ptr.insertBefore(MIR_Move.create(PPC_MFSPR,A(R0),A(phys.getLR())));
  ptr.insertBefore(MIR_StoreUpdate.create(PPC_STAddrU,A(FP),A(FP),IC(-frameSize)));
  ptr.insertBefore(MIR_Store.create(PPC_STAddr,A(R0),A(FP),IC(frameSize + STACKFRAME_NEXT_INSTRUCTION_OFFSET)));
  int cmid=ir.compiledMethod.getId();
  if (cmid <= 0x7fff) {
    ptr.insertBefore(MIR_Unary.create(PPC_LDI,I(R0),IC(cmid)));
  }
 else {
    ptr.insertBefore(MIR_Unary.create(PPC_LDIS,I(R0),IC(cmid >>> 16)));
    ptr.insertBefore(MIR_Binary.create(PPC_ORI,I(R0),I(R0),IC(cmid & 0xffff)));
  }
  ptr.insertBefore(MIR_Store.create(PPC_STW,I(R0),A(FP),IC(STACKFRAME_METHOD_ID_OFFSET)));
  if (ir.compiledMethod.isSaveVolatile()) {
    saveVolatiles(ptr);
  }
  saveNonVolatiles(ptr);
  if (yp) {
    Offset offset=VM_Entrypoints.takeYieldpointField.getOffset();
    if (VM.VerifyAssertions)     VM._assert(OPT_Bits.fits(offset,16));
    ptr.insertBefore(MIR_Load.create(PPC_LInt,I(R0),A(PR),IC(OPT_Bits.PPCMaskLower16(offset))));
    ptr.insertBefore(MIR_Binary.create(PPC_CMPI,I(TSR),I(R0),IC(0)));
  }
}

Fixed version (ground truth):
/** 
 * prologue for the exceptional case. (1) R0 is the only available scratch register. (2) stack overflow check has to come first.
 */
final void insertExceptionalPrologue(){
  if (VM.VerifyAssertions)   VM._assert((frameSize & (STACKFRAME_ALIGNMENT - 1)) == 0,"String_Node_Str");
  if (frameSize >= 0x7ff0) {
    throw new OPT_OptimizingCompilerException("String_Node_Str");
  }
  OPT_PhysicalRegisterSet phys=ir.regpool.getPhysicalRegisterSet();
  OPT_Register FP=phys.getFP();
  OPT_Register PR=phys.getPR();
  OPT_Register TSR=phys.getTSR();
  OPT_Register R0=phys.getTemp();
  OPT_Register S1=phys.getGPR(LAST_SCRATCH_GPR);
  boolean interruptible=ir.method.isInterruptible();
  boolean stackOverflow=interruptible;
  boolean yp=hasPrologueYieldpoint();
  OPT_Instruction ptr=ir.firstInstructionInCodeOrder().nextInstructionInCodeOrder();
  if (VM.VerifyAssertions)   VM._assert(ptr.getOpcode() == IR_PROLOGUE_opcode);
  if (stackOverflow) {
    ptr.insertBefore(MIR_Store.create(PPC_STAddr,A(S1),A(FP),IC(STACKFRAME_NEXT_INSTRUCTION_OFFSET)));
    Offset offset=VM_Entrypoints.activeThreadStackLimitField.getOffset();
    if (VM.VerifyAssertions)     VM._assert(OPT_Bits.fits(offset,16));
    ptr.insertBefore(MIR_Load.create(PPC_LAddr,A(S1),A(phys.getPR()),IC(OPT_Bits.PPCMaskLower16(offset))));
    ptr.insertBefore(MIR_Binary.create(PPC_ADDI,A(R0),A(S1),IC(frameSize)));
    ptr.insertBefore(MIR_Load.create(PPC_LAddr,A(S1),A(FP),IC(STACKFRAME_NEXT_INSTRUCTION_OFFSET)));
    MIR_Trap.mutate(ptr,PPC_TAddr,OPT_PowerPCTrapOperand.LESS(),A(FP),A(R0),OPT_TrapCodeOperand.StackOverflow());
    ptr=ptr.nextInstructionInCodeOrder();
  }
 else {
    OPT_Instruction next=ptr.nextInstructionInCodeOrder();
    ptr.remove();
    ptr=next;
  }
  ptr.insertBefore(MIR_Move.create(PPC_MFSPR,A(R0),A(phys.getLR())));
  ptr.insertBefore(MIR_StoreUpdate.create(PPC_STAddrU,A(FP),A(FP),IC(-frameSize)));
  ptr.insertBefore(MIR_Store.create(PPC_STAddr,A(R0),A(FP),IC(frameSize + STACKFRAME_NEXT_INSTRUCTION_OFFSET)));
  int cmid=ir.compiledMethod.getId();
  if (cmid <= 0x7fff) {
    ptr.insertBefore(MIR_Unary.create(PPC_LDI,I(R0),IC(cmid)));
  }
 else {
    ptr.insertBefore(MIR_Unary.create(PPC_LDIS,I(R0),IC(cmid >>> 16)));
    ptr.insertBefore(MIR_Binary.create(PPC_ORI,I(R0),I(R0),IC(cmid & 0xffff)));
  }
  ptr.insertBefore(MIR_Store.create(PPC_STW,I(R0),A(FP),IC(STACKFRAME_METHOD_ID_OFFSET)));
  if (ir.compiledMethod.isSaveVolatile()) {
    saveVolatiles(ptr);
  }
  saveNonVolatiles(ptr);
  if (yp) {
    Offset offset=VM_Entrypoints.takeYieldpointField.getOffset();
    if (VM.VerifyAssertions)     VM._assert(OPT_Bits.fits(offset,16));
    ptr.insertBefore(MIR_Load.create(PPC_LInt,I(R0),A(PR),IC(OPT_Bits.PPCMaskLower16(offset))));
    ptr.insertBefore(MIR_Binary.create(PPC_CMPI,I(TSR),I(R0),IC(0)));
  }
}