Displaying 20 results from an estimated 585 matches for "nocapture".
2018 Apr 25
2
Help on understanding assume shape array processing and array descriptors in LLVM IR
...,Lj
INTEGER, INTENT(IN) :: Istr, Iend, Jstr,Jend
INTEGER :: i, j
REAL*8, INTENT(INOUT) :: a(Li:,Lj:)
REAL*8, INTENT(IN) :: b(Li:,Lj:)
--snip--
I got the below LLVM IR, the parameters received.
--snip--
; Function Attrs: norecurse nounwind
define void @test_(i64* noalias nocapture %a, i64* noalias nocapture
readonly %b, i64* noalias nocapture readonly %li, i64* noalias
nocapture readonly %lj, i64* noalias nocapture readonly %istr, i64*
noalias nocapture readonly %iend, i64* noalias nocapture readonly
%jstr, i64* noalias nocapture readonly %jend, i64* noalias nocapture
readon...
2018 Apr 25
0
Help on understanding assume shape array processing and array descriptors in LLVM IR
...,Lj
INTEGER, INTENT(IN) :: Istr, Iend, Jstr,Jend
INTEGER :: i, j
REAL*8, INTENT(INOUT) :: a(Li:,Lj:)
REAL*8, INTENT(IN) :: b(Li:,Lj:)
--snip--
I got the below LLVM IR, the parameters received.
--snip--
; Function Attrs: norecurse nounwind
define void @test_(i64* noalias nocapture %a, i64* noalias nocapture
readonly %b, i64* noalias nocapture readonly %li, i64* noalias
nocapture readonly %lj, i64* noalias nocapture readonly %istr, i64*
noalias nocapture readonly %iend, i64* noalias nocapture readonly
%jstr, i64* noalias nocapture readonly %jend, i64* noalias nocapture
readon...
2017 Apr 28
2
Return on nocapture pointer
...u it make sense to extend the definition in LangRef? If so I will be
happy to upload a patch.
Piotr
2017-04-28 17:58 GMT+02:00 Hal Finkel <hfinkel at anl.gov>:
>
>
> On 04/28/2017 10:22 AM, Piotr Padlewski via llvm-dev wrote:
>
> Hi,
> I have a question about semantics of nocapture attribute:
> "This indicates that the callee does not make any copies of the pointer
> that outlive the callee itself. "
> Is returing a pointer considered outliving callee? For example is this
> code valid:
>
>
> Yes, it includes returning the pointer. The code below...
2017 Apr 28
3
Return on nocapture pointer
Hi,
I have a question about semantics of nocapture attribute:
"This indicates that the callee does not make any copies of the pointer
that outlive the callee itself. "
Is returing a pointer considered outliving callee? For example is this code
valid:
define i8* @foo(i8* nocapture %p)
ret i8* %p
}
The documentation also mention that &q...
2012 Oct 08
3
[LLVMdev] Meaning of the nocapture attribute (possible bug?)
Regarding the nocapture attribute the language ref says: "the callee
does not make any copies of the pointer that outlive the callee itself".
>From I inferred that it is OK for the callee to make a copy of the
pointer that doesn't outlive the call. However if I write some code that
does this the optim...
2012 Oct 15
2
[LLVMdev] Meaning of the nocapture attribute (possible bug?)
Is this code valid?
Function f takes a "nocapture" pointer p, and passes it to function g
that does not have nocapture in its parameter list. There is nothing to
stop g from "capturing" p.
-Krzysztof
On 10/8/2012 8:54 AM, Duncan Sands wrote:
> Hi Richard, I think it is a bug.
>
> Ciao, Duncan.
>
> On 08/10/12 14...
2012 Oct 08
0
[LLVMdev] Meaning of the nocapture attribute (possible bug?)
Hi Richard, I think it is a bug.
Ciao, Duncan.
On 08/10/12 14:34, Richard Osborne wrote:
> Regarding the nocapture attribute the language ref says: "the callee does not
> make any copies of the pointer that outlive the callee itself". From I inferred
> that it is OK for the callee to make a copy of the pointer that doesn't outlive
> the call. However if I write some code that does this th...
2020 Jan 22
4
Inlining + CSE + restrict pointers == funtimes
...(see https://godbolt.org/z/-mdjPV):
int called(int* __restrict__ a, int* b, int* c) {
return *a + *b + *c;
}
int foo(int * x, int * y) {
return *x + *y + called(x, x, y);
}
int bar(int * x, int * y) {
return called(x, x, y) + *x + *y;
}
Which becomes:
define dso_local i32 @called(i32* noalias nocapture readonly %0, i32*
nocapture readonly %1, i32* nocapture readonly %2) local_unnamed_addr #0 !
dbg !7 {
%4 = load i32, i32* %0, align 4, !dbg !19, !tbaa !20
%5 = load i32, i32* %1, align 4, !dbg !24, !tbaa !20
%6 = add nsw i32 %5, %4, !dbg !25
%7 = load i32, i32* %2, align 4, !dbg !26, !tbaa !20
%8 =...
2012 May 22
4
[LLVMdev] How to get llvm bitcode executed
...are void @__cxa_end_catch()
declare void @__cxa_call_unexpected(i8*)
declare void @_ZdlPv(i8*) nounwind
declare void @_ZSt20__throw_length_errorPKc(i8*) noreturn
declare void @_ZSt17__throw_bad_allocv() noreturn
declare noalias i8* @_Znwm(i64)
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i32, i1) nounwind
declare void @llvm.memmove.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i32, i1) nounwind
declare i32 @llvm.atomic.load.add.i32.p0i32(i32* nocapture, i32) nounwind
declare void @llvm.memory.barrier(i1, i1, i1, i1, i1) nounwind
declare void @_ZSt20_...
2013 May 21
4
[LLVMdev] malloc / free & memcpy optimisations.
The front end I'm building for an existing interpreted language is
unfortunately producing output similar to this far too often;
define void @foo(i8* nocapture %dest, i8* nocapture %src, i32 %len)
nounwind {
%1 = tail call noalias i8* @malloc(i32 %len) nounwind
tail call void @llvm.memcpy.p0i8.p0i8.i32(i8* %1, i8* %src, i32 %len, i32
1, i1 false)
tail call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dest, i8* %1, i32 %len,
i32 1, i1 false)
tail call void...
2012 Oct 16
0
[LLVMdev] Meaning of the nocapture attribute (possible bug?)
Hi Krzysztof,
> Is this code valid?
yes, I think so.
> Function f takes a "nocapture" pointer p, and passes it to function g that does
> not have nocapture in its parameter list. There is nothing to stop g from
> "capturing" p.
It would be wrong for the optimizers to deduce a nocapture attribute for f in
this context, as they don't know anything about the...
2018 Mar 22
2
new @llvm.memcpy and @llvm.memset API in trunk - how to use alignment?
...parameter. Instead the
docs say to use the align <n> attribute. How is this supposed to work with
different alignments?
For example, I have one memcpy with align 4, align 4, and another with
align 1, align 1.
; Function Attrs: argmemonly nounwind
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture writeonly align 4,
i8* nocapture readonly align 4, i64, i1) #3
; Function Attrs: argmemonly nounwind
declare void @llvm.memcpy.p0i8.p0i8.i64.1(i8* nocapture writeonly align 1,
i8* nocapture readonly align 1, i64, i1) #3
When I add these multiple definitions to the module, llvm mangles the name,...
2011 Mar 24
0
[LLVMdev] mblaze backend: unreachable executed
...oblem are the following:
%196 = call %0 @_Z13gatherDiffuseRK3vecS_S1_RKfS3_Pii(%struct.vec* %normal, double %tmp629, float %174, %struct.vec* %light_position, float* %nohit, float* %epsilon, i32* %66, i32 %5) nounwind
and
define linkonce_odr %0 @_Z13gatherDiffuseRK3vecS_S1_RKfS3_Pii(%struct.vec* nocapture %normal, double %hit_point.0, float %hit_point.1, %struct.vec* nocapture %light_position, float* nocapture %nohit, float* nocapture %epsilon, i32* nocapture %stack, i32 %start_bvh) nounwind inlinehint ssp {
which then goes into the body of the function.
Josef
2011 Mar 15
3
[LLVMdev] mblaze backend: unreachable executed
>> I don't think my backend is modified enough from the MBlaze backend that is
>> in the release to be causing this error. I am however looking through the
>> various files of the backend to try to find where the calling convention
>> might be causing problems with f32 data types.
> Form the backtrace it seems like you haven't defined how to return f32
> stuff
2020 Jun 28
2
__restirct ignored when including headers like <cmath>
...aders.
For example, this code:
void vec_add(int* __restrict a,
int* __restrict b,
int n) {
#pragma unroll 4
for(int i=0; i<n; ++i) {
a[i] += b[i];
}
}
results in:
; Function Attrs: nofree norecurse nounwind
define dso_local void @_Z7vec_addPiS_i(i32* noalias nocapture %a, i32*
noalias nocapture readonly %b, i32 %n) local_unnam
ed_addr #0 {
entry:
.
.
...
(note the noaliass before function arguments).
But this code:
#include <cmath>
void vec_add(int* __restrict a,
int* __restrict b,
int n) {
#pragma unroll 4
for(int i=0...
2012 Oct 16
0
[LLVMdev] Meaning of the nocapture attribute (possible bug?)
Hi all,
Are you sure that the problem here is with the nocapture flag and not
with the noalias?
Removing noalias from the function definition of @f results in the
expected output.
My guess is that something goes wrong in determining that *%q can be
based on %p through @g which results in a 'no alias' relation for the
two where there should be a ...
2014 Jul 10
2
[LLVMdev] Telling the optimizer a value is always null at the start
...yout = "e-m:w-p:32:32-i64:64-f80:32-n8:16:32-S32"
target triple = "i686-pc-windows-msvc"
@str1 = linkonce_odr unnamed_addr constant [3 x i8] c"go\00", align 1
@str2 = linkonce_odr unnamed_addr constant [5 x i8] c"done\00", align 1
define void @inlineeh(i8** nocapture readnone %ex) {
%1 = tail call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([3 x
i8]* @str1, i32 0, i32 0))
ret void
}
declare i32 @printf(i8* nocapture readonly, ...) #0
define void @testeh(i8** nocapture %ex) #0 {
%1 = bitcast i8** %ex to i8*
%2 = tail call {}* @llvm....
2012 May 22
0
[LLVMdev] How to get llvm bitcode executed
...t; declare void @__cxa_call_unexpected(i8*)
> declare void @_ZdlPv(i8*) nounwind
> declare void @_ZSt20__throw_length_errorPKc(i8*) noreturn
> declare void @_ZSt17__throw_bad_allocv() noreturn
> declare noalias i8* @_Znwm(i64)
> declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i32, i1) nounwind
> declare void @llvm.memmove.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i32, i1) nounwind
> declare i32 @llvm.atomic.load.add.i32.p0i32(i32* nocapture, i32) nounwind
> declare void @llvm.memory.barrier(i1, i1, i1, i1, i1) nounwind
> d...
2018 Mar 22
0
new @llvm.memcpy and @llvm.memset API in trunk - how to use alignment?
...use the align <n> attribute. How is this supposed to
> work with different alignments?
>
> For example, I have one memcpy with align 4, align 4, and another with
> align 1, align 1.
>
> ; Function Attrs: argmemonly nounwind
> declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture writeonly align
> 4, i8* nocapture readonly align 4, i64, i1) #3
>
> ; Function Attrs: argmemonly nounwind
> declare void @llvm.memcpy.p0i8.p0i8.i64.1(i8* nocapture writeonly
> align 1, i8* nocapture readonly align 1, i64, i1) #3
>
>
> When I add these multiple definitions...
2017 Apr 26
1
Function LICM for readonly, nocapture functions
...eturn B[0]+B[N-1];
}
Among other optimizations that I may want to happen, I'd hope that the call
to strlen could be moved outside the loop via LICM. Unfortunately, this is
not the case. Looking at the IR I found the following.
The function strlen is marked readonly and the argument is marked nocapture.
; Function Attrs: nounwind readonly
declare i64 @strlen(i8* nocapture) local_unnamed_addr #2
attributes #2 = { nounwind readonly ... }
Presumably this should be enough to permit LICM to move it out of the loop.
Upon a further investigation, the issue appeared to be that
canSinkOrHoistInst did...