[llvm-commits] [llvm] r52818 - in /llvm/trunk: include/llvm/Target/TargetRegisterInfo.h lib/Target/TargetRegisterInfo.cpp

[Evan Cheng]

How about having tblgen create a two-dimensional array that represents  
the aliasing relationship? You can use a bitvector representation, it  
wouldn't be expensive at all if there is one for the whole target.The  
map should be owned by each TargetRegisterInfo. Take a look at the  
code in X86GenRegisterInfo.inc to get a flavor what it would look like.

Evan

On Jun 27, 2008, at 12:27 AM, Owen Anderson wrote:

> I thought this was the approach we'd agreed on at the end of today?   
> I don't know how to have tblgen create this information without  
> attaching it to each TargetRegisterDesc, which will be very costly  
> in terms of memory footprint.
>
> --Owen
>
> On Jun 27, 2008, at 12:19 AM, Evan Cheng wrote:
>
>> Is this really the right approach? I thought we want tblgen at build
>> time to create these matrices to speed up queries. Suppose we are
>> compiling a bunch of small programs. We'd be recomputing the set
>> everytime.
>>
>> Evan
>>
>> On Jun 26, 2008, at 11:56 PM, Owen Anderson wrote:
>>
>>> Author: resistor
>>> Date: Fri Jun 27 01:56:04 2008
>>> New Revision: 52818
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=52818&view=rev
>>> Log:
>>> Cache subregister relationships in a set in TargetRegisterInfo to
>>> allow faster lookups.
>>> This speeds up LiveVariables from 0.6279s to 0.6165s on kimwitu++.
>>>
>>> Modified:
>>>  llvm/trunk/include/llvm/Target/TargetRegisterInfo.h
>>>  llvm/trunk/lib/Target/TargetRegisterInfo.cpp
>>>
>>> Modified: llvm/trunk/include/llvm/Target/TargetRegisterInfo.h
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Target/TargetRegisterInfo.h?rev=52818&r1=52817&r2=52818&view=diff
>>>
>>> =
>>> =
>>> =
>>> =
>>> =
>>> =
>>> =
>>> =
>>> = 
>>> = 
>>> ====================================================================
>>> --- llvm/trunk/include/llvm/Target/TargetRegisterInfo.h (original)
>>> +++ llvm/trunk/include/llvm/Target/TargetRegisterInfo.h Fri Jun 27
>>> 01:56:04 2008
>>> @@ -21,6 +21,7 @@
>>> #include "llvm/CodeGen/ValueTypes.h"
>>> #include <cassert>
>>> #include <functional>
>>> +#include <set>
>>>
>>> namespace llvm {
>>>
>>> @@ -285,6 +286,7 @@
>>> regclass_iterator RegClassBegin, RegClassEnd;   // List of
>>> regclasses
>>>
>>> int CallFrameSetupOpcode, CallFrameDestroyOpcode;
>>> +  std::set<std::pair<unsigned, unsigned> > Subregs;
>>> protected:
>>> TargetRegisterInfo(const TargetRegisterDesc *D, unsigned NR,
>>>                    regclass_iterator RegClassBegin,
>>> @@ -419,9 +421,7 @@
>>> /// isSubRegister - Returns true if regB is a sub-register of regA.
>>> ///
>>> bool isSubRegister(unsigned regA, unsigned regB) const {
>>> -    for (const unsigned *SR = getSubRegisters(regA); *SR; ++SR)
>>> -      if (*SR == regB) return true;
>>> -    return false;
>>> +    return Subregs.count(std::make_pair(regA, regB));
>>> }
>>>
>>> /// isSuperRegister - Returns true if regB is a super-register of
>>> regA.
>>>
>>> Modified: llvm/trunk/lib/Target/TargetRegisterInfo.cpp
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/TargetRegisterInfo.cpp?rev=52818&r1=52817&r2=52818&view=diff
>>>
>>> =
>>> =
>>> =
>>> =
>>> =
>>> =
>>> =
>>> =
>>> = 
>>> = 
>>> ====================================================================
>>> --- llvm/trunk/lib/Target/TargetRegisterInfo.cpp (original)
>>> +++ llvm/trunk/lib/Target/TargetRegisterInfo.cpp Fri Jun 27 01:56:04
>>> 2008
>>> @@ -29,6 +29,16 @@
>>>
>>> CallFrameSetupOpcode   = CFSO;
>>> CallFrameDestroyOpcode = CFDO;
>>> +
>>> +  for (unsigned i = 0; i < NumRegs; ++i) {
>>> +    const TargetRegisterDesc* CurrReg = Desc + i;
>>> +
>>> +    // Initialize the Subregs set, which stores pairs (a, b) where
>>> +    // b is a subreg of a.
>>> +    if (CurrReg->SubRegs)
>>> +      for (const unsigned* CurrSR = CurrReg->SubRegs; *CurrSR; +
>>> +CurrSR)
>>> +        Subregs.insert(std::make_pair(i, *CurrSR));
>>> +  }
>>> }
>>>
>>> TargetRegisterInfo::~TargetRegisterInfo() {}
>>>
>>>
>>> _______________________________________________
>>> llvm-commits mailing list
>>> llvm-commits at cs.uiuc.edu
>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>>
>> _______________________________________________
>> llvm-commits mailing list
>> llvm-commits at cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits