[flang][openacc] Allow multiple wait clauses

[clementval]

Summary

kernels loop and enter data had a too restrictive constraint for the wait clause.
The wait clause is allowed multiple times and not only once. This patch fix this problem.

[SouraVX]

flang/test/Semantics/OpenACC/acc-data.f90

62

Looking at it, I assume wait1 is an event of some kind ? That data create directive is waiting for finishing ?
Then again where is wait1 defined ?
Could you point me to the spec WRT this clause.

[kiranchandramohan]

flang/test/Semantics/OpenACC/acc-data.f90

62

Spec: https://www.openacc.org/sites/default/files/inline-images/Specification/OpenACC-3.1-final.pdf

In Section 2.16.2 it says "If there is an argument to the wait clause, it must be a wait argument (See 2.16.3)."

Section 2.16.3/Page 80

The wait argument, if it appears, must be a wait-argument where wait-argument is:
[ devnum : int-expr : ] [ queues : ] int-expr-list

[clementval]

flang/test/Semantics/OpenACC/acc-data.f90

62

The @kiranchandramohan for mentioning the spec. Basically the most basic wait argument is just a int-expr. You can see it as a stream number in CUDA.

[SouraVX]

LGTM!

flang/test/Semantics/OpenACC/acc-data.f90

62

Thanks for the stream number analogy :)

[clementval]

In D95469#2525380, @SouraVX wrote:

LGTM!

Thanks for all the reviews! Greatly appreciated!

flang/test/Semantics/OpenACC/acc-data.f90

program openacc_data_validity
   !$acc enter data create(aa) async async
 
   !$acc enter data create(aa) async(async1)
 
   !$acc enter data create(aa) async(1)
 
   !$acc enter data create(aa) wait(1)
 
   !$acc enter data create(aa) wait(wait1)
 
   !$acc enter data create(aa) wait(wait1, wait2)
 
+  !$acc enter data create(aa) wait(wait1) wait(wait2)
+
   !$acc enter data attach(bb)
 
   !ERROR: At least one of COPYOUT, DELETE, DETACH clause must appear on the EXIT DATA directive
   !$acc exit data
 
   !ERROR: Modifier is not allowed for the COPYOUT clause on the EXIT DATA directive
   !$acc exit data copyout(zero: i)
 

flang/test/Semantics/OpenACC/acc-kernels-loop.f90

do i = 1, N
     a(i) = 3.14
   end do
 
   !$acc kernels loop wait(wait1, wait2)
   do i = 1, N
     a(i) = 3.14
   end do
 
+  !$acc kernels loop wait(wait1) wait(wait2)
+  do i = 1, N
+    a(i) = 3.14
+  end do
+
   !$acc kernels loop wait(1, 2) async(3)
   do i = 1, N
     a(i) = 3.14
   end do
 
   !$acc kernels loop wait(queues: 1, 2) async(3)
   do i = 1, N
     a(i) = 3.14

llvm/include/llvm/Frontend/OpenACC/ACC.td

def ACC_Wait : Directive<"wait"> {
   let allowedOnceClauses = [
     VersionedClause<ACCC_Async>,
     VersionedClause<ACCC_If>
   ];
 }
 
 // 2.14.6
 def ACC_EnterData : Directive<"enter data"> {
+  let allowedClauses = [
+    VersionedClause<ACCC_Wait>
+  ];
   let allowedOnceClauses = [
     VersionedClause<ACCC_Async>,
-    VersionedClause<ACCC_If>,
-    VersionedClause<ACCC_Wait>
+    VersionedClause<ACCC_If>
   ];
   let requiredClauses = [
     VersionedClause<ACCC_Attach>,
     VersionedClause<ACCC_Create>,
     VersionedClause<ACCC_Copyin>
   ];
 }
 
let allowedClauses = [
     VersionedClause<ACCC_Copyin>,
     VersionedClause<ACCC_Copyout>,
     VersionedClause<ACCC_Create>,
     VersionedClause<ACCC_DeviceType>,
     VersionedClause<ACCC_NoCreate>,
     VersionedClause<ACCC_Present>,
     VersionedClause<ACCC_Private>,
     VersionedClause<ACCC_DevicePtr>,
-    VersionedClause<ACCC_Attach>
+    VersionedClause<ACCC_Attach>,
+    VersionedClause<ACCC_Wait>
   ];
   let allowedOnceClauses = [
     VersionedClause<ACCC_Async>,
     VersionedClause<ACCC_Collapse>,
     VersionedClause<ACCC_Default>,
     VersionedClause<ACCC_Gang>,
     VersionedClause<ACCC_If>,
     VersionedClause<ACCC_NumGangs>,
     VersionedClause<ACCC_NumWorkers>,
     VersionedClause<ACCC_Reduction>,
     VersionedClause<ACCC_Self>,
     VersionedClause<ACCC_Tile>,
     VersionedClause<ACCC_Vector>,
     VersionedClause<ACCC_VectorLength>,
-    VersionedClause<ACCC_Wait>,
     VersionedClause<ACCC_Worker>
   ];
   let allowedExclusiveClauses = [
     VersionedClause<ACCC_Auto>,
     VersionedClause<ACCC_Independent>,
     VersionedClause<ACCC_Seq>
   ];
 }