[flang-commits] [flang] [Flang] Hoist concurrent-limit and concurrent-step expressions outsid… (PR #111665)

[via flang-commits]

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@@ -0,0 +1,50 @@
+! 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
+
+subroutine sub1(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: %[[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 %{{.*}} = %[[LB1_CVT]] to %[[UB1_CVT]] step %{{.*}} unordered
+!CHECK: fir.do_loop %{{.*}} = %[[LB2_CVT]] to %[[UB2_CVT]] step %{{.*}} unordered
+   do concurrent(i=1:n, j=1:bar(n*m, n/m))
+      a(i) = n
+   end do
+end subroutine
+
+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: %[[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 %{{.*}} = %[[LB1_CVT]] to %[[UB1_CVT]] step %{{.*}} unordered
+!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
----------------
jeanPerier wrote:

This case is different than sub1 since 11.1.7.4.2 does not say that the concurrent limit and steps of all nested do concurrent construct must be performed before the outter constructs.

You can have:
```
subroutine sub3(a, n)
   implicit none
   integer :: n
   integer, dimension(n, n) :: a
   do concurrent(integer::i=1:n)
      do concurrent(integer::j=1:i)
         a(i, j) = n
      end do
   end do
end subroutine


  integer :: a(4,4) = -1
  call sub3(a, 4)
  print *, a
end
```

This is a valid program, and with your current patch it will compile to invalid code that will most likely segfault at runtime.

https://github.com/llvm/llvm-project/pull/111665