[flang][cuda] Add restriction on assumed size device variable

[clementval]

According to https://docs.nvidia.com/hpc-sdk/compilers/cuda-fortran-prog-guide/#cfpg-var-qual-attr-device

A device array may be an explicit-shape array, an allocatable array, or an assumed-shape dummy array.

Assumed size array are not supported. This patch adds an error for that case.

[llvmbot]

@llvm/pr-subscribers-flang-semantics

Author: Valentin Clement (バレンタイン クレメン) (clementval)

Changes

According to https://docs.nvidia.com/hpc-sdk/compilers/cuda-fortran-prog-guide/#cfpg-var-qual-attr-device

> A device array may be an explicit-shape array, an allocatable array, or an assumed-shape dummy array.

Assumed size array are not supported. This patch adds an error for that case.

---

Full diff: https://github.com/llvm/llvm-project/pull/87664.diff

2 Files Affected:

• (modified) flang/lib/Semantics/check-declarations.cpp (+5)
• (modified) flang/test/Semantics/cuf03.cuf (+2-1)

diff --git a/flang/lib/Semantics/check-declarations.cpp b/flang/lib/Semantics/check-declarations.cpp
index dec8fee774c5be..b2de37759a0613 100644
--- a/flang/lib/Semantics/check-declarations.cpp
+++ b/flang/lib/Semantics/check-declarations.cpp
@@ -948,6 +948,11 @@ void CheckHelper::CheckObjectEntity(
             "Component '%s' with ATTRIBUTES(DEVICE) must also be allocatable"_err_en_US,
             symbol.name());
       }
+      if (IsAssumedSizeArray(symbol)) {
+        messages_.Say(
+            "Object '%s' with ATTRIBUTES(DEVICE) may not be assumed size"_err_en_US,
+            symbol.name());
+      }
       break;
     case common::CUDADataAttr::Managed:
       if (!IsAutomatic(symbol) && !IsAllocatable(symbol) &&
diff --git a/flang/test/Semantics/cuf03.cuf b/flang/test/Semantics/cuf03.cuf
index 41bfbb76781364..7384a104831d8d 100644
--- a/flang/test/Semantics/cuf03.cuf
+++ b/flang/test/Semantics/cuf03.cuf
@@ -51,7 +51,8 @@ module m
  contains
   attributes(device) subroutine devsubr(n,da)
     integer, intent(in) :: n
-    real, device :: da(*) ! ok
+    !ERROR: Object 'da' with ATTRIBUTES(DEVICE) may not be assumed size
+    real, device :: da(*)
     real, managed :: ma(n) ! ok
     !WARNING: Pointer 'dp' may not be associated in a device subprogram
     real, device, pointer :: dp