[llvm-commits] [llvm] r50663 - in /llvm/trunk: include/llvm/ include/llvm/CodeGen/ include/llvm/Target/ lib/CodeGen/ lib/CodeGen/SelectionDAG/ lib/Target/ lib/Target/X86/ test/CodeGen/X86/

[Mon P Wang]

Hi Evan,

I'll make that change that you suggested.  As for the llvm-gcc, I'll  
make that change later when I get some time.  I'm currently using clang.

Thanks,
    -- Mon Ping


On May 5, 2008, at 2:00 PM, Evan Cheng wrote:

> Hi Mon Ping,
>
> Some comments.
>
> On May 5, 2008, at 12:05 PM, Mon P Wang wrote:
>
>>
>> @@ -5732,6 +5744,187 @@
>> //                           X86 Scheduler Hooks
>> //
>> =
>> =
>> =
>> ----------------------------------------------------------------------=
>> ==//
>>
>> +// private utility function
>> +MachineBasicBlock *
>> +X86TargetLowering::EmitAtomicBitwiseWithCustomInserter(MachineInstr
>> *bInstr,
>> +
>> MachineBasicBlock *MBB,
>> +                                                       unsigned
>> regOpc,
>> +                                                       unsigned
>> immOpc) {
>> +  // For the atomic bitwise operator, we generate
>> +  //   thisMBB:
>> +  //   newMBB:
>> +  //     ld  EAX = [bitinstr.addr]
>> +  //     mov t1 = EAX
>> +  //     op  t2 = t1, [bitinstr.val]
>
> I think this is not quite right. lcs implicitly uses EAX so the value
> should be copied *to* EAX.  Also, only forcing the value into EAX just
> before its use is (slightly) better for register allocation.
>
> t1 = ld [addr]
> t2 = op t1, birinstr.val
> eax = mov t1
>
>>
>> +  //     lcs dest = [bitinstr.addr], t2  [EAX is implicit]
>> +  //     bz  newMBB
>> +  //     fallthrough -->nextMBB
>> +  const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
>> +  const BasicBlock *LLVM_BB = MBB->getBasicBlock();
>> +  ilist<MachineBasicBlock>::iterator MBBIter = MBB;
>> +  ++MBBIter;
>> +
>
> Also, are you implementing llvm-gcc changes to enable it to generate
> these intrinsics?
>
> Thanks,
>
> Evan
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