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Dmitry Polukhin via llvm-dev

2015-Dec-08 11:38 UTC

[llvm-dev] Field sensitive alias analysis?

Jeroen, thank you for very useful link with the context. Indeed union cases
are very complicated and I see places in code when TBAA gives up.

Daniel, I completely agree that TBAA has limited power and can solve
relatively simple cases only. So anything more complicated that involves
intermediate variables that points to struct or array elements cannot be
solved by TBAA alone. Differentiating array subscripts also seems like out
of the scope of TBAA but adding type information that this memory assess
accessing array not a random object of given type could be useful.
Therefore TBAA can compliment points-to analysis and sometimes help in
cases when points-to may not have enough information.

On Mon, Dec 7, 2015 at 7:43 PM, Daniel Berlin <dberlin at dberlin.org>
wrote:
> TBAA is about types, not accesses.
> TBAA "struct path data" is about access paths and types that are
the end
> of access paths, for the most part.
>
> It has no notion of access size, etc, only offset.
>
> It is possible to extend it and handle *very basic* cases in the frontend
> (IE structs not containing unions anywhere, with constant accesses, etc)
> But it would degrade quite quickly (you would likely need a sane way to
> say "this is an access to an unknown offset into this type")
>
> Generally, rather than just try to produce metadata in the frontend, most
> compilers perform field-sensitive points-to or something similar for
> fields, and then rely on data dependence for differentiating array
> subscripts.
>
> (This is what GCC does, LLVM has CFL-AA, but it's not field sensitive
yet)
>
> So handling .size vs .a[] is probably possible in the frontend.
>
> Doing array subscript analysis in general, probably not something you want
> in the frontend.
> Handling tricky cases of what pointers to structs point to, probably the
> domain of field-sensitive points-to
>
> On Mon, Dec 7, 2015 at 7:13 AM, Dmitry Polukhin via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>> BTW, I have found why it doesn't work for arrays. TBAA information
>> propagation is not implemented in
CodeGenFunction::EmitArraySubscriptExpr
>> with "TODO: Preserve/extend path TBAA metadata?".
>>
>> On Fri, Dec 4, 2015 at 1:38 PM, Dmitry Polukhin <
>> dmitry.polukhin at gmail.com> wrote:
>>
>>> As far as I can see it is specifics of arrays inside structs.
Current
>>> TBAA does distinguish non-array members with path sensitive TBAA
(see !1
>>> and !6 in my example below, TBAA has reference to struct !2 and
offset). As
>>> for arrays information that it was member of some struct get lost
>>> completely (!7 has nothing about struct !2).
>>>
>>> struct S {
>>>   int a;
>>>   int b;
>>>   int c[3];
>>> };
>>>
>>> void foo(struct S* p) {
>>>   p->a = 1;
>>>   p->b = 2;
>>>   p->c[0] = 3;
>>>   p->c[1] = 4;
>>> }
>>>
>>> define void @foo(%struct.S* nocapture %p) #0 {
>>> entry:
>>>   %a = getelementptr inbounds %struct.S, %struct.S* %p, i64 0, i32
0
>>>   store i32 1, i32* %a, align 4, !tbaa !1
>>>   %b = getelementptr inbounds %struct.S, %struct.S* %p, i64 0, i32
1
>>>   store i32 2, i32* %b, align 4, !tbaa !6
>>>   %arrayidx = getelementptr inbounds %struct.S, %struct.S* %p, i64
0,
>>> i32 2, i64 0
>>>   store i32 3, i32* %arrayidx, align 4, !tbaa !7
>>>   %arrayidx2 = getelementptr inbounds %struct.S, %struct.S* %p, i64
0,
>>> i32 2, i64 1
>>>   store i32 4, i32* %arrayidx2, align 4, !tbaa !7
>>>   ret void
>>> }
>>>
>>> !0 = !{!"clang version 3.8.0 "}
>>> !1 = !{!2, !3, i64 0}
>>> !2 = !{!"S", !3, i64 0, !3, i64 4, !4, i64 8}
>>> !3 = !{!"int", !4, i64 0}
>>> !4 = !{!"omnipotent char", !5, i64 0}
>>> !5 = !{!"Simple C/C++ TBAA"}
>>> !6 = !{!2, !3, i64 4}
>>> !7 = !{!3, !3, i64 0}
>>>
>>> I'm just start learning how TBAA in clang works so I don't
know why it
>>> was implemented this way.
>>>
>>> On Fri, Dec 4, 2015 at 11:06 AM, Vaivaswatha Nagaraj via llvm-dev
<
>>> llvm-dev at lists.llvm.org> wrote:
>>>
>>>> Hi,
>>>>
>>>> I'm trying to optimize a simple C code and came across a
situation
>>>> where invariant code is not being moved out:
>>>>
>>>> On an -O3 compilation, I noticed that the "load" for
the loop bounds
>>>> (which remain invariant throughout) happens on each iteration
of both the
>>>> loops, even though it is not modified anywhere in the function
"bigLoop".
>>>> It seems that alias analysis is not able to say that the writes
to one
>>>> field in the structure does not impact the other field, leading
to LICM
>>>> being ineffective.
>>>>
>>>> Do any of the alias analyses currently have some kind of field
>>>> sensitivity that can help in this case?
>>>>
>>>> ------------------------- test case
------------------------------------
>>>> #include <stdlib.h>
>>>> #include <stdio.h>
>>>>
>>>> #define SIZE 100
>>>>
>>>> struct AS {
>>>>   int a[SIZE+4];
>>>>   int size;
>>>> } A;
>>>>
>>>> void bigLoop(void)
>>>> {
>>>>   unsigned i, j;
>>>>
>>>>   for (i = 0; i < A.size; i++) {
>>>>     A.a[i+2] +=  A.a[i];
>>>>   }
>>>>   for (i = 0; i < A.size; i++) {
>>>>     A.a[i+2] *=  A.a[i];
>>>>   }
>>>> }
>>>>
>>>> int main()
>>>> {
>>>>   A.size = random()%SIZE;
>>>>   for (unsigned i = 0; i < A.size; i++) {
>>>>     A.a[i] = random()%23;
>>>>   }
>>>>   bigLoop();
>>>>   return 0;
>>>> }
>>>>
>>>> Thanks,
>>>>
>>>>   - Vaivaswatha
>>>>
>>>> _______________________________________________
>>>> LLVM Developers mailing list
>>>> llvm-dev at lists.llvm.org
>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>>
>>>>
>>>
>>
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
>>
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Daniel Berlin via llvm-dev

2015-Dec-08 15:44 UTC

head link

[llvm-dev] Field sensitive alias analysis?

Just remember that to LLVM, TBAA info doesn't tell it about types.

So when you say " Differentiating array subscripts also seems like out of
the scope of TBAA but adding type information that this memory assess
accessing array not a random object of given type could be useful."

Remember that LLVM has no notion of C/C++ types.

It doesn't know about them, it doesn't care about them.

What TBAA is telling it is that certain memory locations are disjoint.
It will *never* understand that what is being accessed is "a C++ struct
containing an array of shorts", because the type system doesn't know
what a
"C struct" is, or a "C array" or a  "C short".

Thus, while helpful, TBAA info in LLVM tells it *nothing* about the types,
it only tells it that "if i am accessing this offset, it is disjoint with
accessing this other offset".


On Tue, Dec 8, 2015 at 3:38 AM, Dmitry Polukhin <dmitry.polukhin at
gmail.com>
wrote:
> Jeroen, thank you for very useful link with the context. Indeed union
> cases are very complicated and I see places in code when TBAA gives up.
>
> Daniel, I completely agree that TBAA has limited power and can solve
> relatively simple cases only. So anything more complicated that involves
> intermediate variables that points to struct or array elements cannot be
> solved by TBAA alone. Differentiating array subscripts also seems like out
> of the scope of TBAA but adding type information that this memory assess
> accessing array not a random object of given type could be useful.
> Therefore TBAA can compliment points-to analysis and sometimes help in
> cases when points-to may not have enough information.
>
> On Mon, Dec 7, 2015 at 7:43 PM, Daniel Berlin <dberlin at
dberlin.org> wrote:
>
>> TBAA is about types, not accesses.
>> TBAA "struct path data" is about access paths and types that
are the end
>> of access paths, for the most part.
>>
>> It has no notion of access size, etc, only offset.
>>
>> It is possible to extend it and handle *very basic* cases in the
frontend
>> (IE structs not containing unions anywhere, with constant accesses,
etc)
>> But it would degrade quite quickly (you would likely need a sane way to
>> say "this is an access to an unknown offset into this type")
>>
>> Generally, rather than just try to produce metadata in the frontend,
most
>> compilers perform field-sensitive points-to or something similar for
>> fields, and then rely on data dependence for differentiating array
>> subscripts.
>>
>> (This is what GCC does, LLVM has CFL-AA, but it's not field
sensitive yet)
>>
>> So handling .size vs .a[] is probably possible in the frontend.
>>
>> Doing array subscript analysis in general, probably not something you
>> want in the frontend.
>> Handling tricky cases of what pointers to structs point to, probably
the
>> domain of field-sensitive points-to
>>
>> On Mon, Dec 7, 2015 at 7:13 AM, Dmitry Polukhin via llvm-dev <
>> llvm-dev at lists.llvm.org> wrote:
>>
>>> BTW, I have found why it doesn't work for arrays. TBAA
information
>>> propagation is not implemented in
CodeGenFunction::EmitArraySubscriptExpr
>>> with "TODO: Preserve/extend path TBAA metadata?".
>>>
>>> On Fri, Dec 4, 2015 at 1:38 PM, Dmitry Polukhin <
>>> dmitry.polukhin at gmail.com> wrote:
>>>
>>>> As far as I can see it is specifics of arrays inside structs.
Current
>>>> TBAA does distinguish non-array members with path sensitive
TBAA (see !1
>>>> and !6 in my example below, TBAA has reference to struct !2 and
offset). As
>>>> for arrays information that it was member of some struct get
lost
>>>> completely (!7 has nothing about struct !2).
>>>>
>>>> struct S {
>>>>   int a;
>>>>   int b;
>>>>   int c[3];
>>>> };
>>>>
>>>> void foo(struct S* p) {
>>>>   p->a = 1;
>>>>   p->b = 2;
>>>>   p->c[0] = 3;
>>>>   p->c[1] = 4;
>>>> }
>>>>
>>>> define void @foo(%struct.S* nocapture %p) #0 {
>>>> entry:
>>>>   %a = getelementptr inbounds %struct.S, %struct.S* %p, i64 0,
i32 0
>>>>   store i32 1, i32* %a, align 4, !tbaa !1
>>>>   %b = getelementptr inbounds %struct.S, %struct.S* %p, i64 0,
i32 1
>>>>   store i32 2, i32* %b, align 4, !tbaa !6
>>>>   %arrayidx = getelementptr inbounds %struct.S, %struct.S* %p,
i64 0,
>>>> i32 2, i64 0
>>>>   store i32 3, i32* %arrayidx, align 4, !tbaa !7
>>>>   %arrayidx2 = getelementptr inbounds %struct.S, %struct.S* %p,
i64 0,
>>>> i32 2, i64 1
>>>>   store i32 4, i32* %arrayidx2, align 4, !tbaa !7
>>>>   ret void
>>>> }
>>>>
>>>> !0 = !{!"clang version 3.8.0 "}
>>>> !1 = !{!2, !3, i64 0}
>>>> !2 = !{!"S", !3, i64 0, !3, i64 4, !4, i64 8}
>>>> !3 = !{!"int", !4, i64 0}
>>>> !4 = !{!"omnipotent char", !5, i64 0}
>>>> !5 = !{!"Simple C/C++ TBAA"}
>>>> !6 = !{!2, !3, i64 4}
>>>> !7 = !{!3, !3, i64 0}
>>>>
>>>> I'm just start learning how TBAA in clang works so I
don't know why it
>>>> was implemented this way.
>>>>
>>>> On Fri, Dec 4, 2015 at 11:06 AM, Vaivaswatha Nagaraj via
llvm-dev <
>>>> llvm-dev at lists.llvm.org> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> I'm trying to optimize a simple C code and came across
a situation
>>>>> where invariant code is not being moved out:
>>>>>
>>>>> On an -O3 compilation, I noticed that the "load"
for the loop bounds
>>>>> (which remain invariant throughout) happens on each
iteration of both the
>>>>> loops, even though it is not modified anywhere in the
function "bigLoop".
>>>>> It seems that alias analysis is not able to say that the
writes to one
>>>>> field in the structure does not impact the other field,
leading to LICM
>>>>> being ineffective.
>>>>>
>>>>> Do any of the alias analyses currently have some kind of
field
>>>>> sensitivity that can help in this case?
>>>>>
>>>>> ------------------------- test case
>>>>> ------------------------------------
>>>>> #include <stdlib.h>
>>>>> #include <stdio.h>
>>>>>
>>>>> #define SIZE 100
>>>>>
>>>>> struct AS {
>>>>>   int a[SIZE+4];
>>>>>   int size;
>>>>> } A;
>>>>>
>>>>> void bigLoop(void)
>>>>> {
>>>>>   unsigned i, j;
>>>>>
>>>>>   for (i = 0; i < A.size; i++) {
>>>>>     A.a[i+2] +=  A.a[i];
>>>>>   }
>>>>>   for (i = 0; i < A.size; i++) {
>>>>>     A.a[i+2] *=  A.a[i];
>>>>>   }
>>>>> }
>>>>>
>>>>> int main()
>>>>> {
>>>>>   A.size = random()%SIZE;
>>>>>   for (unsigned i = 0; i < A.size; i++) {
>>>>>     A.a[i] = random()%23;
>>>>>   }
>>>>>   bigLoop();
>>>>>   return 0;
>>>>> }
>>>>>
>>>>> Thanks,
>>>>>
>>>>>   - Vaivaswatha
>>>>>
>>>>> _______________________________________________
>>>>> LLVM Developers mailing list
>>>>> llvm-dev at lists.llvm.org
>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>>>
>>>>>
>>>>
>>>
>>> _______________________________________________
>>> LLVM Developers mailing list
>>> llvm-dev at lists.llvm.org
>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>
>>>
>>
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Dmitry Polukhin via llvm-dev

2015-Dec-09 10:33 UTC

head link

[llvm-dev] Field sensitive alias analysis?

Hi Daniel,

I see your point about LLVM and C/C++ type agnostic. I think TBAA was
invented to partially cover this gap and give optimization opportunities
when LLVM types are not sufficient but C/C++ types have required
information.

What do you think about following example:
struct S {
  int a[10];
  int b;
};

int foo(struct S *ps, int i) {
  ps->a[i] = 1;
  ps->b = 2;
  return ps->a[0];
}

define i32 @foo(%struct.S* nocapture %ps, i32 %i) #0 {
entry:
  %idxprom = sext i32 %i to i64
  %arrayidx = getelementptr inbounds %struct.S, %struct.S* %ps, i64 0, i32
0, i64 %idxprom
  store i32 1, i32* %arrayidx, align 4, !tbaa !1
  %b = getelementptr inbounds %struct.S, %struct.S* %ps, i64 0, i32 1
  store i32 2, i32* %b, align 4, !tbaa !5
  %arrayidx2 = getelementptr inbounds %struct.S, %struct.S* %ps, i64 0, i32
0, i64 0
  %0 = load i32, i32* %arrayidx2, align 4, !tbaa !1
  ret i32 %0
}

!1 = !{!2, !2, i64 0}
!2 = !{!"int", !3, i64 0}
!3 = !{!"omnipotent char", !4, i64 0}
!4 = !{!"Simple C/C++ TBAA"}
!5 = !{!6, !2, i64 40}
!6 = !{!"S", !3, i64 0, !2, i64 40}

Missing information here is the range inside struct S that could be
accessed. Also as you can see array member of struct in TBAA is presented
as omnipotent char not as an array of int.

Arrays in struct in TBAA can be represented something like this:
!6 = !{!"S", !7, i64 0, !2, i64 40}
!7 = !{!"<unique id of int[10]>", !2, i64 0}

And 'ps->a[i]' could have TBAA like this:
!8 = !{!6, !7, i64 0}

As far as I can see if struct is enclosed in another struct, information
about inner struct get lost only offset present. But I think for arrays it
is better to keep array type in TBAA for the struct and element accesses.

    Dmitry

On Tue, Dec 8, 2015 at 6:44 PM, Daniel Berlin <dberlin at dberlin.org>
wrote:
> Just remember that to LLVM, TBAA info doesn't tell it about types.
>
> So when you say " Differentiating array subscripts also seems like out
of
> the scope of TBAA but adding type information that this memory assess
> accessing array not a random object of given type could be useful."
>
> Remember that LLVM has no notion of C/C++ types.
>
> It doesn't know about them, it doesn't care about them.
>
> What TBAA is telling it is that certain memory locations are disjoint.
> It will *never* understand that what is being accessed is "a C++
struct
> containing an array of shorts", because the type system doesn't
know what a
> "C struct" is, or a "C array" or a  "C
short".
>
> Thus, while helpful, TBAA info in LLVM tells it *nothing* about the types,
> it only tells it that "if i am accessing this offset, it is disjoint
with
> accessing this other offset".
>
>
> On Tue, Dec 8, 2015 at 3:38 AM, Dmitry Polukhin <dmitry.polukhin at
gmail.com
> > wrote:
>
>> Jeroen, thank you for very useful link with the context. Indeed union
>> cases are very complicated and I see places in code when TBAA gives up.
>>
>> Daniel, I completely agree that TBAA has limited power and can solve
>> relatively simple cases only. So anything more complicated that
involves
>> intermediate variables that points to struct or array elements cannot
be
>> solved by TBAA alone. Differentiating array subscripts also seems like
out
>> of the scope of TBAA but adding type information that this memory
assess
>> accessing array not a random object of given type could be useful.
>> Therefore TBAA can compliment points-to analysis and sometimes help in
>> cases when points-to may not have enough information.
>>
>> On Mon, Dec 7, 2015 at 7:43 PM, Daniel Berlin <dberlin at
dberlin.org>
>> wrote:
>>
>>> TBAA is about types, not accesses.
>>> TBAA "struct path data" is about access paths and types
that are the end
>>> of access paths, for the most part.
>>>
>>> It has no notion of access size, etc, only offset.
>>>
>>> It is possible to extend it and handle *very basic* cases in the
>>> frontend (IE structs not containing unions anywhere, with constant
>>> accesses, etc)
>>> But it would degrade quite quickly (you would likely need a sane
way to
>>> say "this is an access to an unknown offset into this
type")
>>>
>>> Generally, rather than just try to produce metadata in the
frontend,
>>> most compilers perform field-sensitive points-to or something
similar for
>>> fields, and then rely on data dependence for differentiating array
>>> subscripts.
>>>
>>> (This is what GCC does, LLVM has CFL-AA, but it's not field
sensitive
>>> yet)
>>>
>>> So handling .size vs .a[] is probably possible in the frontend.
>>>
>>> Doing array subscript analysis in general, probably not something
you
>>> want in the frontend.
>>> Handling tricky cases of what pointers to structs point to,
probably the
>>> domain of field-sensitive points-to
>>>
>>> On Mon, Dec 7, 2015 at 7:13 AM, Dmitry Polukhin via llvm-dev <
>>> llvm-dev at lists.llvm.org> wrote:
>>>
>>>> BTW, I have found why it doesn't work for arrays. TBAA
information
>>>> propagation is not implemented in
CodeGenFunction::EmitArraySubscriptExpr
>>>> with "TODO: Preserve/extend path TBAA metadata?".
>>>>
>>>> On Fri, Dec 4, 2015 at 1:38 PM, Dmitry Polukhin <
>>>> dmitry.polukhin at gmail.com> wrote:
>>>>
>>>>> As far as I can see it is specifics of arrays inside
structs. Current
>>>>> TBAA does distinguish non-array members with path sensitive
TBAA (see !1
>>>>> and !6 in my example below, TBAA has reference to struct !2
and offset). As
>>>>> for arrays information that it was member of some struct
get lost
>>>>> completely (!7 has nothing about struct !2).
>>>>>
>>>>> struct S {
>>>>>   int a;
>>>>>   int b;
>>>>>   int c[3];
>>>>> };
>>>>>
>>>>> void foo(struct S* p) {
>>>>>   p->a = 1;
>>>>>   p->b = 2;
>>>>>   p->c[0] = 3;
>>>>>   p->c[1] = 4;
>>>>> }
>>>>>
>>>>> define void @foo(%struct.S* nocapture %p) #0 {
>>>>> entry:
>>>>>   %a = getelementptr inbounds %struct.S, %struct.S* %p, i64
0, i32 0
>>>>>   store i32 1, i32* %a, align 4, !tbaa !1
>>>>>   %b = getelementptr inbounds %struct.S, %struct.S* %p, i64
0, i32 1
>>>>>   store i32 2, i32* %b, align 4, !tbaa !6
>>>>>   %arrayidx = getelementptr inbounds %struct.S, %struct.S*
%p, i64 0,
>>>>> i32 2, i64 0
>>>>>   store i32 3, i32* %arrayidx, align 4, !tbaa !7
>>>>>   %arrayidx2 = getelementptr inbounds %struct.S, %struct.S*
%p, i64 0,
>>>>> i32 2, i64 1
>>>>>   store i32 4, i32* %arrayidx2, align 4, !tbaa !7
>>>>>   ret void
>>>>> }
>>>>>
>>>>> !0 = !{!"clang version 3.8.0 "}
>>>>> !1 = !{!2, !3, i64 0}
>>>>> !2 = !{!"S", !3, i64 0, !3, i64 4, !4, i64 8}
>>>>> !3 = !{!"int", !4, i64 0}
>>>>> !4 = !{!"omnipotent char", !5, i64 0}
>>>>> !5 = !{!"Simple C/C++ TBAA"}
>>>>> !6 = !{!2, !3, i64 4}
>>>>> !7 = !{!3, !3, i64 0}
>>>>>
>>>>> I'm just start learning how TBAA in clang works so I
don't know why it
>>>>> was implemented this way.
>>>>>
>>>>> On Fri, Dec 4, 2015 at 11:06 AM, Vaivaswatha Nagaraj via
llvm-dev <
>>>>> llvm-dev at lists.llvm.org> wrote:
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> I'm trying to optimize a simple C code and came
across a situation
>>>>>> where invariant code is not being moved out:
>>>>>>
>>>>>> On an -O3 compilation, I noticed that the
"load" for the loop bounds
>>>>>> (which remain invariant throughout) happens on each
iteration of both the
>>>>>> loops, even though it is not modified anywhere in the
function "bigLoop".
>>>>>> It seems that alias analysis is not able to say that
the writes to one
>>>>>> field in the structure does not impact the other field,
leading to LICM
>>>>>> being ineffective.
>>>>>>
>>>>>> Do any of the alias analyses currently have some kind
of field
>>>>>> sensitivity that can help in this case?
>>>>>>
>>>>>> ------------------------- test case
>>>>>> ------------------------------------
>>>>>> #include <stdlib.h>
>>>>>> #include <stdio.h>
>>>>>>
>>>>>> #define SIZE 100
>>>>>>
>>>>>> struct AS {
>>>>>>   int a[SIZE+4];
>>>>>>   int size;
>>>>>> } A;
>>>>>>
>>>>>> void bigLoop(void)
>>>>>> {
>>>>>>   unsigned i, j;
>>>>>>
>>>>>>   for (i = 0; i < A.size; i++) {
>>>>>>     A.a[i+2] +=  A.a[i];
>>>>>>   }
>>>>>>   for (i = 0; i < A.size; i++) {
>>>>>>     A.a[i+2] *=  A.a[i];
>>>>>>   }
>>>>>> }
>>>>>>
>>>>>> int main()
>>>>>> {
>>>>>>   A.size = random()%SIZE;
>>>>>>   for (unsigned i = 0; i < A.size; i++) {
>>>>>>     A.a[i] = random()%23;
>>>>>>   }
>>>>>>   bigLoop();
>>>>>>   return 0;
>>>>>> }
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>>   - Vaivaswatha
>>>>>>
>>>>>> _______________________________________________
>>>>>> LLVM Developers mailing list
>>>>>> llvm-dev at lists.llvm.org
>>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>>>>
>>>>>>
>>>>>
>>>>
>>>> _______________________________________________
>>>> LLVM Developers mailing list
>>>> llvm-dev at lists.llvm.org
>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>>
>>>>
>>>
>>
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