DoConcurrentLoop¶
A loop whose iterations may run in any order.
Declaration¶
Syntax¶
DoConcurrentLoop(do_loop_head* head, expr* shared, expr* local,
reduction_expr* reduction, stmt* body)
Arguments¶
Argument |
Description |
|---|---|
|
one do_loop_head per index, giving the index variable and its range. Several heads mean a nest of concurrent indices. |
|
the variables shared by all iterations. |
|
the variables each iteration has its own copy of. |
|
the reductions, each a reduction_expr pairing an operator with the variable it accumulates into. |
|
the statements of one iteration. |
Return values¶
None.
Description¶
do concurrent asserts that the iterations do not depend on each other, so a
backend may run them in any order or in parallel. ASR records the assertion
and the data environment; it does not check it.
The locality lists say what each iteration sees. A variable in local is
private to an iteration, a variable in shared is not, and a variable in
reduction is combined across iterations with the named operator.
Examples¶
An ASR text document that uses it:
(TranslationUnit
:symtab (SymbolTable
:id 0
:symbols {
"main" (Program
:symtab (SymbolTable
:id 1
:symbols {
"a" (Variable
:parent_symtab 1
:name "a"
:dependencies []
:intent :Local
:symbolic_value nil
:value nil
:storage :Default
:type (Array
:type (Integer
:kind 4
)
:dims [
(dimension
:start (IntegerConstant
:n 1
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
:length (IntegerConstant
:n 3
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
)
]
:physical_type :FixedSizeArray
)
:type_declaration nil
:abi :Source
:access :Public
:presence :Required
:value_attr false
:target_attr false
:contiguous_attr false
:bindc_name nil
:is_volatile false
:is_protected false
:pass_attr :NotMethod
:self_argument nil
:codims []
)
"i" (Variable
:parent_symtab 1
:name "i"
:dependencies []
:intent :Local
:symbolic_value nil
:value nil
:storage :Default
:type (Integer
:kind 4
)
:type_declaration nil
:abi :Source
:access :Public
:presence :Required
:value_attr false
:target_attr false
:contiguous_attr false
:bindc_name nil
:is_volatile false
:is_protected false
:pass_attr :NotMethod
:self_argument nil
:codims []
)
"total" (Variable
:parent_symtab 1
:name "total"
:dependencies []
:intent :Local
:symbolic_value nil
:value nil
:storage :Default
:type (Integer
:kind 4
)
:type_declaration nil
:abi :Source
:access :Public
:presence :Required
:value_attr false
:target_attr false
:contiguous_attr false
:bindc_name nil
:is_volatile false
:is_protected false
:pass_attr :NotMethod
:self_argument nil
:codims []
)
}
)
:name "main"
:dependencies []
:body [
(DoConcurrentLoop
:head [
(do_loop_head
:v (Var
:v (SymbolRef 1 "i")
)
:start (IntegerConstant
:n 1
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
:end (IntegerConstant
:n 3
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
:increment (IntegerConstant
:n 1
:type (Integer
:kind 4
)
:intboz_type :Decimal
)
)
]
:shared [
(Var
:v (SymbolRef 1 "a")
)
]
:local [
(Var
:v (SymbolRef 1 "i")
)
]
:reduction [
(reduction_expr
:op :ReduceAdd
:arg (Var
:v (SymbolRef 1 "total")
)
)
]
:body [
(Assignment
:target (ArrayItem
:v (Var
:v (SymbolRef 1 "a")
)
:args [
(array_index
:left nil
:right (Var
:v (SymbolRef 1 "i")
)
:step nil
)
]
:type (Integer
:kind 4
)
:storage_format :ColMajor
:value nil
)
:value (Var
:v (SymbolRef 1 "i")
)
:overloaded nil
:realloc_lhs false
:move_allocation false
)
]
)
]
)
}
)
:items []
)