DoConcurrentLoop¶
DoConcurrentLoop specifies that there are no data dependencies between the iterations of a DO loop.
Declaration¶
Syntax¶
DoConcurrentLoop(do_loop_head head, stmt* body)
Arguments¶
head contains do loop concurrent header.
body contains loop body.
Return values¶
None.
Description¶
DoConcurrentLoop specifies that there are no data dependecies between the
iterations of a DO loop. Within the body of a DoConcurrent loop the program
must adgere to a the list of restrictions specified on its use of Fortran
language features. Actions that can’t be executed in parallel or that don’t
allow all iterations to execute are prohibited, like:
Control flow statements which prevents the loop nest from executing all its iterations.
Image control statements, like
STOP,SYNC,ALLOCATE/DEALLOCATE.
Types¶
Accessible global identifier and a sequence of zero or more statements or
construst that make the DO range.
Examples¶
program doconcurrentloop
implicit none
real, dimension(10) :: a
real :: sum
integer :: N, i
N = size(a)
sum = 0
do concurrent (i = 1:N)
a(i) = a(i-1) + 5
end do
call arraySum(a, sum)
contains
subroutine arraySum(a, sum)
real, intent(in) :: a(:)
real, intent(out) :: sum
do concurrent (i = 1:N) reduce(+: s)
sum = sum + a(i)
end do
end subroutine
end program
ASR:
(TranslationUnit
(SymbolTable
1
{
doconcurrentloop_02:
(Program
(SymbolTable
2
{
a:
(Variable
2
a
Local
()
()
Default
(Real 4 [((IntegerConstant 1 (Integer 4 []))
(IntegerConstant 10 (Integer 4 [])))])
Source
Public
Required
.false.
),
arraysum:
(Function
(SymbolTable
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{
a:
(Variable
3
a
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()
()
Default
(Real 4 [(()
())])
Source
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Required
.false.
),
sum:
(Variable
3
sum
Out
()
()
Default
(Real 4 [])
Source
Public
Required
.false.
)
})
arraysum
[(Var 3 a)
(Var 3 sum)]
[(DoConcurrentLoop
((Var 2 i)
(IntegerConstant 1 (Integer 4 []))
(Var 2 n)
())
[(=
(Var 3 sum)
(RealBinOp
(Var 3 sum)
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(ArrayItem
(Var 3 a)
[(()
(Var 2 i)
())]
(Real 4 [])
()
)
(Real 4 [])
()
)
()
)]
)]
()
Source
Public
Implementation
()
.false.
.false.
.false.
.false.
.false.
[]
[]
.false.
),
i:
(Variable
2
i
Local
()
()
Default
(Integer 4 [])
Source
Public
Required
.false.
),
n:
(Variable
2
n
Local
()
()
Default
(Integer 4 [])
Source
Public
Required
.false.
),
sum:
(Variable
2
sum
Local
()
()
Default
(Real 4 [])
Source
Public
Required
.false.
)
})
doconcurrentloop_02
[]
[(=
(Var 2 n)
(ArraySize
(Var 2 a)
()
(Integer 4 [])
(IntegerConstant 10 (Integer 4 []))
)
()
)
(=
(Var 2 sum)
(Cast
(IntegerConstant 0 (Integer 4 []))
IntegerToReal
(Real 4 [])
(RealConstant
0.000000
(Real 4 [])
)
)
()
)
(DoConcurrentLoop
((Var 2 i)
(IntegerConstant 1 (Integer 4 []))
(Var 2 n)
())
[(=
(ArrayItem
(Var 2 a)
[(()
(Var 2 i)
())]
(Real 4 [])
()
)
(RealBinOp
(ArrayItem
(Var 2 a)
[(()
(IntegerBinOp
(Var 2 i)
Sub
(IntegerConstant 1 (Integer 4 []))
(Integer 4 [])
()
)
())]
(Real 4 [])
()
)
Add
(Cast
(IntegerConstant 5 (Integer 4 []))
IntegerToReal
(Real 4 [])
(RealConstant
5.000000
(Real 4 [])
)
)
(Real 4 [])
()
)
()
)]
)
(SubroutineCall
2 arraysum
()
[((Var 2 a))
((Var 2 sum))]
()
)]
)
})
[]
)