[flang][openacc] Fix false positive error in common block resolution

[clementval]

Summary

The following error was triggered in the added test case.
This is a false positive.

COMMON block must be declared in the same scoping unit in which the OpenACC directive or clause appears

[kiranchandramohan]

LG.

flang/lib/Semantics/resolve-directives.cpp

if (!symbol->owner().IsDerivedType() && !symbol->has<ProcEntityDetails>() &&
         }
       }
     }
   } // within OpenACC construct
 }
 
 Symbol *AccAttributeVisitor::ResolveAccCommonBlockName(
     const parser::Name *name) {
-  if (!name) {
-    return nullptr;
-  } else if (auto *prev{
-                 GetContext().scope.parent().FindCommonBlock(name->source)}) {
+  if (auto *prev{name
+              ? GetContext().scope.parent().FindCommonBlock(name->source)
+              : nullptr}) {
     name->symbol = prev;
     return prev;
-  } else {
-    return nullptr;
   }
+  // Check if the Common Block is declared in the current scope
+  if (auto *commonBlockSymbol{
+          name ? GetContext().scope.FindCommonBlock(name->source) : nullptr}) {
+    name->symbol = commonBlockSymbol;
+    return commonBlockSymbol;
+  }
+  return nullptr;
 }
 
 void AccAttributeVisitor::ResolveAccObjectList(
     const parser::AccObjectList &accObjectList, Symbol::Flag accFlag) {
   for (const auto &accObject : accObjectList.v) {
     ResolveAccObject(accObject, accFlag);
   }
 }

flang/test/Semantics/OpenACC/acc-resolve04.f90

 ! RUN: %flang_fc1 -fopenacc %s
 
+! Check common block resolution.
 ! Check that symbol are correctly resolved in device, host and self clause.
 
+subroutine sub(a)
+ implicit none
+ real :: a(10)
+ real :: b(10), c(10), d
+ common/foo/ b, d, c
+ integer :: i, n
+
+ !$acc declare present(/foo/)
+ !$acc parallel loop gang vector
+  do i = 1, n
+    b(i) = a(i) + c(i) * d
+  end do
+end subroutine
+
 program test_resolve04
   real :: a(10), b(10)
   common /foo/ b, c
 
 !$acc data create(/foo/)
 !$acc update device(/foo/)
 !$acc update host(/foo/)
 !$acc update self(/foo/)
 !$acc end data
 
 !$acc data copy(/foo/)
 !$acc end data
 
 end