[LLVMdev] Tablegen bug???

Chris Lattner clattner at apple.com
Fri Nov 30 20:08:25 PST 2012

Yes that definitely sounds like a bug, no intrinsically in mainline are a prefix if another one, or we are getting lucky.


On Nov 29, 2012, at 7:24 PM, "Relph, Richard" <Richard.Relph at amd.com> wrote:

> If the source being scanned has "llvm.AMDIL.barrier.global, it will match the first barrier test and return AMDIL_barrier, not AMDIL_barrier_global.
> On Nov 29, 2012, at 7:19 PM, Chris Lattner <clattner at apple.com>
> wrote:
>> Out of curiosity, what is wrong about that?  It looks ok to me.
>> -Chris
>> On Nov 29, 2012, at 6:52 PM, "Relph, Richard" <Richard.Relph at amd.com> wrote:
>>>  Should tablegen detect this as an error, or is it documented as a limitation somewhere that we've missed?
>>>  In the tablegen-generated file AMDILGenIntrinsics.inc, we have a bunch of if statements comparing strings, many of which are dead, preventing correct recognition of some intrinsics in the their text form. I'm not quite sure what GET_FUNCTION_RECOGNIZER is used for, but if it's used, it's broken… ;-)
>>>  Here's a small segment:
>>> // Function name -> enum value recognizer code.
>>> StringRef NameR(Name+6, Len-6);   // Skip over 'llvm.'
>>> switch (Name[5]) {                  // Dispatch on first letter.
>>> default: break;
>>> case 'A':
>>>>>> if (NameR.startswith("MDIL.barrier.")) return AMDILIntrinsic::AMDIL_barrier;
>>> if (NameR.startswith("MDIL.barrier.global.")) return AMDILIntrinsic::AMDIL_barrier_global;
>>> if (NameR.startswith("MDIL.barrier.local.")) return AMDILIntrinsic::AMDIL_barrier_local;
>>> if (NameR.startswith("MDIL.barrier.region.")) return AMDILIntrinsic::AMDIL_barrier_region;
>>>>>> if (NameR.startswith("MDIL.fma.")) return AMDILIntrinsic::AMDIL_fma;
>>> if (NameR.startswith("MDIL.fma.rte.")) return AMDILIntrinsic::AMDIL_fma_rte;
>>> if (NameR.startswith("MDIL.fma.rtn.")) return AMDILIntrinsic::AMDIL_fma_rtn;
>>> if (NameR.startswith("MDIL.fma.rtp.")) return AMDILIntrinsic::AMDIL_fma_rtp;
>>> if (NameR.startswith("MDIL.fma.rtz.")) return AMDILIntrinsic::AMDIL_fma_rtz;
>>>>>> and several other similar instances.
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