[LLVMdev] MFENCE encoding

[Evan Cheng]

I've fixed this (untested though).
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20081013/068611.html

Evan

On Oct 17, 2008, at 9:51 AM, Evan Cheng wrote:

> Hmm. mfence and lfence needs special handling. I'll take a look.
>
> Evan
>
> On Oct 16, 2008, at 10:46 PM, Mon Ping Wang wrote:
>
>> Hi,
>>
>> I have a problem with creating a MFENCE on X86 with SSE
>>
>> In X86InstrSSE.td, a MFENCE is
>> def MFENCE : I<0xAE, MRM6m, (outs), (ins),
>>              "mfence", [(int_x86_sse2_mfence)]>, TB, Requires<
>> [HasSSE2]>;
>>
>> In X86CodeEmitter.cpp in emitInstruction
>>
>> case X86II::MRM6m: case X86II::MRM7m: {
>>   intptr_t PCAdj = (CurOp+4 != NumOps) ?
>>     (MI.getOperand(CurOp+4).isImm() ? X86InstrInfo::sizeOfImm
>> (Desc) : 4) : 0;
>>   ...
>>
>> If I'm reading the code correctly, the NumOps is 0 and CurOp is 0 so
>> we to get the 4th operand from the MFENCE operation which has no
>> operands so we get an error.  I'm not sure what this code is trying  
>> to
>> do.  Should the condition be < NumOps?
>>
>> Thanks,
>> -- Mon Ping
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