[LLVMdev] about MemoryDependenceAnalysis usage

Willy WOLFF willy.mh.wolff at gmail.com
Mon May 11 08:13:21 PDT 2015 

Yes it is.

On 11/05/2015 17:11, Daniel Berlin wrote:
> intriguiging.
> Is your pass a modulepass, or what?
>
>
> On Mon, May 11, 2015 at 8:04 AM, Willy WOLFF <willy.mh.wolff at gmail.com> wrote:
>> Thanks for your quick answer.
>> But it's still the same:
>> opt -o /dev/null test.ll -S -load ./libPlaydep.so -O3 -basicaa -playdep
>> --debug-pass=Structure
>> Pass Arguments:  -targetlibinfo -datalayout -notti -basictti -x86tti -no-aa
>> -tbaa -scoped-noalias -assumption-cache-tracker -basicaa -verify-di -ipsccp
>> -globalopt -deadargelim -domtree -instcombine -simplifycfg -basiccg
>> -prune-eh -inline-cost -inline -functionattrs -argpromotion -sroa -domtree
>> -early-cse -lazy-value-info -jump-threading -correlated-propagation
>> -simplifycfg -domtree -instcombine -tailcallelim -simplifycfg -reassociate
>> -domtree -loops -loop-simplify -lcssa -loop-rotate -licm -loop-unswitch
>> -instcombine -scalar-evolution -loop-simplify -lcssa -indvars -loop-idiom
>> -loop-deletion -function_tti -loop-unroll -memdep -mldst-motion -domtree
>> -memdep -gvn -memdep -memcpyopt -sccp -domtree -instcombine -lazy-value-info
>> -jump-threading -correlated-propagation -domtree -memdep -dse -adce
>> -simplifycfg -domtree -instcombine -barrier -domtree -loops -loop-simplify
>> -lcssa -branch-prob -block-freq -scalar-evolution -loop-vectorize
>> -instcombine -scalar-evolution -slp-vectorizer -simplifycfg -domtree
>> -instcombine -loops -loop-simplify -lcssa -scalar-evolution -function_tti
>> -loop-unroll -alignment-from-assumptions -strip-dead-prototypes -globaldce
>> -constmerge -playdep -verify -verify-di -print-module
>> Target Library Information
>> Data Layout
>> No target information
>> Target independent code generator's TTI
>> X86 Target Transform Info
>> No Alias Analysis (always returns 'may' alias)
>> Type-Based Alias Analysis
>> Scoped NoAlias Alias Analysis
>> Assumption Cache Tracker
>> Basic Alias Analysis (stateless AA impl)
>>    ModulePass Manager
>>      Debug Info Verifier
>>      Interprocedural Sparse Conditional Constant Propagation
>> ....
>>       Module Verifier
>>      Debug Info Verifier
>>      Print module to stderr
>> Pass Arguments:  -no-aa -assumption-cache-tracker -targetlibinfo -basicaa
>> No Alias Analysis (always returns 'may' alias)
>> Assumption Cache Tracker
>> Target Library Information
>> Basic Alias Analysis (stateless AA impl)
>>    ModulePass Manager
>>      Unnamed pass: implement Pass::getPassName()
>>        Unnamed pass: implement Pass::getPassName()
>> Pass Arguments:  -assumption-cache-tracker -no-aa -memdep
>> Assumption Cache Tracker
>> No Alias Analysis (always returns 'may' alias)
>>    FunctionPass Manager
>>      Memory Dependence Analysis
>> function fct
>> for this instruction:   store i32 2, i32* %6, align 4, !tbaa !5
>> deps are:
>>    %5 = load i32** %4, align 8, !tbaa !1
>>    store i32 1, i32* %3, align 4, !tbaa !5
>>    %2 = load i32** %1, align 8, !tbaa !1
>>
>>
>> On 11/05/2015 16:50, Daniel Berlin wrote:
>>>
>>> add -basicaa to your command line :)
>>>
>>> On Mon, May 11, 2015 at 7:15 AM, Willy WOLFF <willy.mh.wolff at gmail.com>
>>> wrote:
>>>>
>>>> I play a bit more with MemoryDependenceAnalysis by wrapping my pass, and
>>>> call explicitely BasicAliasAnalysis. Its still using No Alias Analysis.
>>>>
>>>> How can I let MemoryDependenceAnalysis use BasicAliasAnalysis?
>>>>
>>>> Please, find attached my pass.
>>>>
>>>> I call my pass like this: "opt -o /dev/null -S test.ll -load
>>>> libPlaydep.so
>>>> -O3 -playdep --debug-pass=Structure"
>>>> And the output:
>>>>
>>>> opt -o /dev/null test.ll -S -load ./libPlaydep.so -O3 -playdep
>>>> --debug-pass=Structure
>>>> Pass Arguments:  -targetlibinfo -datalayout -notti -basictti -x86tti
>>>> -no-aa
>>>> -tbaa -scoped-noalias -assumption-cache-tracker -basicaa -verify-di
>>>> -ipsccp
>>>> -globalopt -deadargelim -domtree -instcombine -simplifycfg -basiccg
>>>> -prune-eh -inline-cost -inline -functionattrs -argpromotion -sroa
>>>> -domtree
>>>> -early-cse -lazy-value-info -jump-threading -correlated-propagation
>>>> -simplifycfg -domtree -instcombine -tailcallelim -simplifycfg
>>>> -reassociate
>>>> -domtree -loops -loop-simplify -lcssa -loop-rotate -licm -loop-unswitch
>>>> -instcombine -scalar-evolution -loop-simplify -lcssa -indvars -loop-idiom
>>>> -loop-deletion -function_tti -loop-unroll -memdep -mldst-motion -domtree
>>>> -memdep -gvn -memdep -memcpyopt -sccp -domtree -instcombine
>>>> -lazy-value-info
>>>> -jump-threading -correlated-propagation -domtree -memdep -dse -adce
>>>> -simplifycfg -domtree -instcombine -barrier -domtree -loops
>>>> -loop-simplify
>>>> -lcssa -branch-prob -block-freq -scalar-evolution -loop-vectorize
>>>> -instcombine -scalar-evolution -slp-vectorizer -simplifycfg -domtree
>>>> -instcombine -loops -loop-simplify -lcssa -scalar-evolution -function_tti
>>>> -loop-unroll -alignment-from-assumptions -strip-dead-prototypes
>>>> -globaldce
>>>> -constmerge -playdep -verify -verify-di -print-module
>>>> Target Library Information
>>>> Data Layout
>>>> No target information
>>>> Target independent code generator's TTI
>>>> X86 Target Transform Info
>>>> No Alias Analysis (always returns 'may' alias)
>>>> Type-Based Alias Analysis
>>>> Scoped NoAlias Alias Analysis
>>>> Assumption Cache Tracker
>>>> Basic Alias Analysis (stateless AA impl)
>>>>     ModulePass Manager
>>>>       Debug Info Verifier
>>>>       Interprocedural Sparse Conditional Constant Propagation
>>>>       Global Variable Optimizer
>>>> .....
>>>>       FunctionPass Manager
>>>>         Module Verifier
>>>>       Debug Info Verifier
>>>>       Print module to stderr
>>>> Pass Arguments:  -no-aa -assumption-cache-tracker -targetlibinfo -basicaa
>>>> No Alias Analysis (always returns 'may' alias)
>>>> Assumption Cache Tracker
>>>> Target Library Information
>>>> Basic Alias Analysis (stateless AA impl)
>>>>     ModulePass Manager
>>>>       Unnamed pass: implement Pass::getPassName()
>>>>         Unnamed pass: implement Pass::getPassName()
>>>> Pass Arguments:  -assumption-cache-tracker -no-aa -memdep
>>>> Assumption Cache Tracker
>>>> No Alias Analysis (always returns 'may' alias)
>>>>     FunctionPass Manager
>>>>       Memory Dependence Analysis
>>>> function fct
>>>> for this instruction:   store i32 2, i32* %6, align 4, !tbaa !5
>>>> deps are:
>>>>     %5 = load i32** %4, align 8, !tbaa !1
>>>>     store i32 1, i32* %3, align 4, !tbaa !5
>>>>     %2 = load i32** %1, align 8, !tbaa !1
>>>>
>>>>
>>>> Cheers,
>>>> Willy
>>>>
>>>>
>>>> On 09/05/2015 16:06, Willy WOLFF wrote:
>>>>>
>>>>>
>>>>> Hi,
>>>>>
>>>>> I try to use MemoryDependenceAnalysis in a pass to analyse a simple
>>>>> function:
>>>>>
>>>>> void fct (int *restrict*restrict M, int *restrict*restrict L) {
>>>>> S1:    M[1][1] = 1;
>>>>> S2:    L[2][2] = 2;
>>>>> }
>>>>>
>>>>> When I iterate over MemoryDependenceAnalysis on the S2 statement, I get
>>>>> the load instruction for the first depth of the array, that’s ok. But I
>>>>> get
>>>>> also the load and store for the S1 statement.
>>>>> I assume the restrict keywoard help the alias analysis to found that
>>>>> pointers don’t alias.
>>>>> The prototype of this function in llvm-ir is:
>>>>> define void @fct(i32** noalias %M, i32** noalias %L) #0 { ….
>>>>>
>>>>> Did this noalias attribute say that both pointer of i32** didn’t alias?
>>>>>
>>>>> Also, when I check wich AliasAnalysis pass is called with
>>>>> —debug-pass=Structure, I see that Memory Dependence Analysis use No
>>>>> Alias
>>>>> Analysis, even if I use -O3 before calling my pass. Can we specify which
>>>>> AlisAnalysis we want to use inside the pass (in getAnalysisUsage method,
>>>>> or
>>>>> somewhere else)?
>>>>>
>>>>> Regards,
>>>>> Willy
>>>>>
>>>>
>>>> _______________________________________________
>>>> LLVM Developers mailing list
>>>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>>>>
>>
>> --
>> Willy WOLFF
>> Etudiant en Master d'informatique à l'Université de Strasbourg
>> Ingénierie du Logiciel et des Connaissances, 2em année.
>> 06.09.72.81.51 | willy.wolff at etu.unistra.fr

-- 
Willy WOLFF
Etudiant en Master d'informatique à l'Université de Strasbourg
Ingénierie du Logiciel et des Connaissances, 2em année.
06.09.72.81.51 | willy.wolff at etu.unistra.fr

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