[clang] [OpenMP] Add variable capture support for transparent clause expression. (PR #185419)

[Abhinav Gaba via cfe-commits]

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@@ -39,78 +41,132 @@ void TestTaskTransparent() {
 }
 #endif
 
-
 // CHECK: FunctionDecl {{.*}} TestTaskTransparent 'void ()'
 // CHECK: OMPTaskDirective
 // CHECK-NEXT: OMPTransparentClause
-// CHECK-NEXT: ImplicitCastExpr {{.*}} 'omp_impex_t':'void **' <LValueToRValue>
 // CHECK-NEXT: DeclRefExpr {{.*}} 'const omp_impex_t':'void **const' lvalue Var {{.*}} 'omp_not_impex' 'const omp_impex_t':'void **const'
 // CHECK-NEXT: OMPFirstprivateClause
 // CHECK-NEXT: DeclRefExpr {{.*}} 'omp_impex_t':'void **' lvalue Var {{.*}} 'imp' 'omp_impex_t':'void **' refers_to_enclosing_variable_or_capture
+// CHECK-NEXT: DeclRefExpr {{.*}} 'int' lvalue Var {{.*}} 'a' 'int' refers_to_enclosing_variable_or_capture
 // CHECK-NEXT: CapturedStmt
 // CHECK: OMPTaskDirective
 // CHECK-NEXT: OMPTransparentClause
-// CHECK-NEXT: ImplicitCastExpr {{.*}} 'omp_impex_t':'void **' <LValueToRValue>
 // CHECK-NEXT: DeclRefExpr {{.*}} 'omp_impex_t':'void **' lvalue Var {{.*}} 'imp' 'omp_impex_t':'void **' refers_to_enclosing_variable_or_capture
+// CHECK-NEXT: OMPFirstprivateClause
+// CHECK-NEXT: DeclRefExpr {{.*}} 'int' lvalue Var {{.*}} 'a' 'int' refers_to_enclosing_variable_or_capture
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abhinavgaba wrote:

`load i32, ptr %a` should happen before scheduling the task, so there is no need to imply `firstprivate(a)` on a task on which `transparent(a)` is present.

The implicit reference should only affect the outer constructs. So if we had:

```c
  #pragma omp task // (1)
  {
    #pragma omp task transparent(a) // (2)
    {...}
  }
```

The "implcit reference" should cause an implicit `firstprivate(a)` on the outer task `(1)`, not the inner task `(2)`.

https://github.com/llvm/llvm-project/pull/185419