llvm-project/flang/test/Lower/do_concurrent.f90
Kareem Ergawy 0698482506
[flang][MLIR] Hoist do concurrent nest bounds/steps outside the nest (#114020)
If you have the following multi-range `do concurrent` loop:

```fortran
  do concurrent(i=1:n, j=1:bar(n*m, n/m))
    a(i) = n
  end do
```

Currently, flang generates the following IR:

```mlir
    fir.do_loop %arg1 = %42 to %44 step %c1 unordered {
      ...
      %53:3 = hlfir.associate %49 {adapt.valuebyref} : (i32) -> (!fir.ref<i32>, !fir.ref<i32>, i1)
      %54:3 = hlfir.associate %52 {adapt.valuebyref} : (i32) -> (!fir.ref<i32>, !fir.ref<i32>, i1)
      %55 = fir.call @_QFPbar(%53#1, %54#1) fastmath<contract> : (!fir.ref<i32>, !fir.ref<i32>) -> i32
      hlfir.end_associate %53#1, %53#2 : !fir.ref<i32>, i1
      hlfir.end_associate %54#1, %54#2 : !fir.ref<i32>, i1
      %56 = fir.convert %55 : (i32) -> index
      ...
      fir.do_loop %arg2 = %46 to %56 step %c1_4 unordered {
        ...
      }
    }
```

However, if `bar` is impure, then we have a direct violation of the
standard:

```
C1143 A reference to an impure procedure shall not appear within a DO CONCURRENT construct.
```

Moreover, the standard describes the execution of `do concurrent`
construct in multiple stages:

```
11.1.7.4 Execution of a DO construct
...
11.1.7.4.2 DO CONCURRENT loop control
The concurrent-limit and concurrent-step expressions in the concurrent-control-list are evaluated. ...

11.1.7.4.3 The execution cycle
...
The block of a DO CONCURRENT construct is executed for every active combination of the index-name values.
Each execution of the block is an iteration. The executions may occur in any order.
```

From the above 2 points, it seems to me that execution is divided in
multiple consecutive stages: 11.1.7.4.2 is the stage where we evaluate
all control expressions including the step and then 11.1.7.4.3 is the
stage to execute the block of the concurrent loop itself using the
combination of possible iteration values.
2024-10-31 09:19:18 +01:00

103 lines
3.8 KiB
Fortran

! RUN: %flang_fc1 -emit-hlfir -o - %s | FileCheck %s
! Simple tests for structured concurrent loops with loop-control.
pure function bar(n, m)
implicit none
integer, intent(in) :: n, m
integer :: bar
bar = n + m
end function
!CHECK-LABEL: sub1
subroutine sub1(n)
implicit none
integer :: n, m, i, j, k
integer, dimension(n) :: a
!CHECK: %[[LB1:.*]] = arith.constant 1 : i32
!CHECK: %[[LB1_CVT:.*]] = fir.convert %[[LB1]] : (i32) -> index
!CHECK: %[[UB1:.*]] = fir.load %{{.*}}#0 : !fir.ref<i32>
!CHECK: %[[UB1_CVT:.*]] = fir.convert %[[UB1]] : (i32) -> index
!CHECK: %[[LB2:.*]] = arith.constant 1 : i32
!CHECK: %[[LB2_CVT:.*]] = fir.convert %[[LB2]] : (i32) -> index
!CHECK: %[[UB2:.*]] = fir.call @_QPbar(%{{.*}}, %{{.*}}) proc_attrs<pure> fastmath<contract> : (!fir.ref<i32>, !fir.ref<i32>) -> i32
!CHECK: %[[UB2_CVT:.*]] = fir.convert %[[UB2]] : (i32) -> index
!CHECK: %[[LB3:.*]] = arith.constant 5 : i32
!CHECK: %[[LB3_CVT:.*]] = fir.convert %[[LB3]] : (i32) -> index
!CHECK: %[[UB3:.*]] = arith.constant 10 : i32
!CHECK: %[[UB3_CVT:.*]] = fir.convert %[[UB3]] : (i32) -> index
!CHECK: fir.do_loop %{{.*}} = %[[LB1_CVT]] to %[[UB1_CVT]] step %{{.*}} unordered
!CHECK: fir.do_loop %{{.*}} = %[[LB2_CVT]] to %[[UB2_CVT]] step %{{.*}} unordered
!CHECK: fir.do_loop %{{.*}} = %[[LB3_CVT]] to %[[UB3_CVT]] step %{{.*}} unordered
do concurrent(i=1:n, j=1:bar(n*m, n/m), k=5:10)
a(i) = n
end do
end subroutine
!CHECK-LABEL: sub2
subroutine sub2(n)
implicit none
integer :: n, m, i, j
integer, dimension(n) :: a
!CHECK: %[[LB1:.*]] = arith.constant 1 : i32
!CHECK: %[[LB1_CVT:.*]] = fir.convert %[[LB1]] : (i32) -> index
!CHECK: %[[UB1:.*]] = fir.load %5#0 : !fir.ref<i32>
!CHECK: %[[UB1_CVT:.*]] = fir.convert %[[UB1]] : (i32) -> index
!CHECK: fir.do_loop %{{.*}} = %[[LB1_CVT]] to %[[UB1_CVT]] step %{{.*}} unordered
!CHECK: %[[LB2:.*]] = arith.constant 1 : i32
!CHECK: %[[LB2_CVT:.*]] = fir.convert %[[LB2]] : (i32) -> index
!CHECK: %[[UB2:.*]] = fir.call @_QPbar(%{{.*}}, %{{.*}}) proc_attrs<pure> fastmath<contract> : (!fir.ref<i32>, !fir.ref<i32>) -> i32
!CHECK: %[[UB2_CVT:.*]] = fir.convert %[[UB2]] : (i32) -> index
!CHECK: fir.do_loop %{{.*}} = %[[LB2_CVT]] to %[[UB2_CVT]] step %{{.*}} unordered
do concurrent(i=1:n)
do concurrent(j=1:bar(n*m, n/m))
a(i) = n
end do
end do
end subroutine
!CHECK-LABEL: unstructured
subroutine unstructured(inner_step)
integer(4) :: i, j, inner_step
!CHECK-NOT: cf.br
!CHECK-NOT: cf.cond_br
!CHECK: %[[LB1:.*]] = arith.constant 1 : i32
!CHECK: %[[LB1_CVT:.*]] = fir.convert %c1_i32 : (i32) -> i16
!CHECK: %[[UB1:.*]] = arith.constant 5 : i32
!CHECK: %[[UB1_CVT:.*]] = fir.convert %c5_i32 : (i32) -> i16
!CHECK: %[[STP1:.*]] = arith.constant 1 : i16
!CHECK-NOT: cf.br
!CHECK-NOT: cf.cond_br
!CHECK: %[[LB2:.*]] = arith.constant 3 : i32
!CHECK: %[[LB2_CVT:.*]] = fir.convert %[[LB2]] : (i32) -> i16
!CHECK: %[[UB2:.*]] = arith.constant 9 : i32
!CHECK: %[[UB2_CVT:.*]] = fir.convert %[[UB2]] : (i32) -> i16
!CHECK: %[[STP2:.*]] = fir.load %{{.*}}#0 : !fir.ref<i32>
!CHECK: %[[STP2_CVT:.*]] = fir.convert %[[STP2]] : (i32) -> i16
!CHECK: fir.store %[[STP2_CVT]] to %{{.*}} : !fir.ref<i16>
!CHECK: cf.br ^[[I_LOOP_HEADER:.*]]
!CHECK: ^[[I_LOOP_HEADER]]:
!CHECK-NEXT: %{{.*}} = fir.load %{{.*}} : !fir.ref<i16>
!CHECK-NEXT: %{{.*}} = arith.constant 0 : i16
!CHECK-NEXT: %{{.*}} = arith.cmpi sgt, %{{.*}}, %{{.*}}: i16
!CHECK-NEXT: cf.cond_br %{{.*}}, ^[[J_LOOP_HEADER:.*]], ^{{.*}}
!CHECK: ^[[J_LOOP_HEADER]]:
!CHECK-NEXT: %[[RANGE:.*]] = arith.subi %[[UB2_CVT]], %[[LB2_CVT]] : i16
!CHECK-NEXT: %{{.*}} = arith.addi %[[RANGE]], %[[STP2_CVT]] : i16
!CHECK-NEXT: %{{.*}} = arith.divsi %{{.*}}, %[[STP2_CVT]] : i16
do concurrent (integer(2)::i=1:5, j=3:9:inner_step, i.ne.3)
goto (7, 7) i+1
print*, 'E:', i, j
7 continue
enddo
end subroutine unstructured