[flang-commits] [flang] ab6cc6b - [flang] Allow nested scopes for implied DO loops with DATA statements (#129410)

[via flang-commits]

Author: Eugene Epshteyn
Date: 2025-03-04T20:41:01-05:00
New Revision: ab6cc6b7b3a3de5e6f5999601f0d40ab2b2819e2

URL: https://github.com/llvm/llvm-project/commit/ab6cc6b7b3a3de5e6f5999601f0d40ab2b2819e2
DIFF: https://github.com/llvm/llvm-project/commit/ab6cc6b7b3a3de5e6f5999601f0d40ab2b2819e2.diff

LOG: [flang] Allow nested scopes for implied DO loops with DATA statements (#129410)

Previously, nested scopes for implied DO loops with DATA statements were
disallowed, which meant that the following code couldn't compile due to
re-use of `j` loop variable name:
    
    DATA (a(i),(b(i,j),j=1,3),(c(i,j),j=1,3),i=0,4)/
    
This change allows nested scopes implied DO loops, which allows the code
above to compile.

Tests modified to in accordance with this change:
Semantics/resolve40.f90, Semantics/symbol09.f90

Added: 
    

Modified: 
    flang/lib/Semantics/resolve-names.cpp
    flang/test/Semantics/resolve40.f90
    flang/test/Semantics/symbol09.f90

Removed: 
    


################################################################################
diff  --git a/flang/lib/Semantics/resolve-names.cpp b/flang/lib/Semantics/resolve-names.cpp
index 02b91f15e7cf4..2a2daf1575a2b 100644
--- a/flang/lib/Semantics/resolve-names.cpp
+++ b/flang/lib/Semantics/resolve-names.cpp
@@ -7490,15 +7490,10 @@ bool ConstructVisitor::Pre(const parser::DataImpliedDo &x) {
   Walk(bounds.upper);
   Walk(bounds.step);
   EndCheckOnIndexUseInOwnBounds(restore);
-  bool pushScope{currScope().kind() != Scope::Kind::ImpliedDos};
-  if (pushScope) {
-    PushScope(Scope::Kind::ImpliedDos, nullptr);
-  }
+  PushScope(Scope::Kind::ImpliedDos, nullptr);
   DeclareStatementEntity(bounds.name, type);
   Walk(objects);
-  if (pushScope) {
-    PopScope();
-  }
+  PopScope();
   return false;
 }
 
@@ -7539,9 +7534,9 @@ bool ConstructVisitor::Pre(const parser::DataStmtObject &x) {
             }
           },
           [&](const parser::DataImpliedDo &y) {
-            PushScope(Scope::Kind::ImpliedDos, nullptr);
+            // Don't push scope here, since it's done when visiting
+            // DataImpliedDo.
             Walk(y);
-            PopScope();
           },
       },
       x.u);

diff  --git a/flang/test/Semantics/resolve40.f90 b/flang/test/Semantics/resolve40.f90
index b3384a91097d7..a91507aa62282 100644
--- a/flang/test/Semantics/resolve40.f90
+++ b/flang/test/Semantics/resolve40.f90
@@ -69,8 +69,8 @@ subroutine s8
 
 subroutine s9
   real :: x(2,2)
-  !ERROR: 'i' is already declared in this scoping unit
-  data ((x(i,i),i=1,2),i=1,2)/4*0.0/
+  ! Nested implied DO loops have their own scope
+  data ((x(i,j),j=1,2),(x(i,j),j=1,2),i=1,2)/8*0.0/
 end
 
 module m10

diff  --git a/flang/test/Semantics/symbol09.f90 b/flang/test/Semantics/symbol09.f90
index 98cd1d954c3e7..0ed80b55b34d1 100644
--- a/flang/test/Semantics/symbol09.f90
+++ b/flang/test/Semantics/symbol09.f90
@@ -51,7 +51,7 @@ subroutine s3
  real, dimension(n,n) :: x
  !REF: /s3/x
  !DEF: /s3/ImpliedDos1/k (Implicit) ObjectEntity INTEGER(4)
- !DEF: /s3/ImpliedDos1/j ObjectEntity INTEGER(8)
+ !DEF: /s3/ImpliedDos1/ImpliedDos1/j ObjectEntity INTEGER(8)
  !REF: /s3/n
  !REF: /s3/n2
  data ((x(k,j),integer(kind=8)::j=1,n),k=1,n)/n2*3.0/