[flang-commits] [flang] 392cba8 - [flang] Handle optional TARGET associate in ASSOCIATED runtime

[Jean Perier via flang-commits]

Author: Jean Perier
Date: 2022-03-03T10:11:35+01:00
New Revision: 392cba8603efc41991613d3b3faaca21fd322500

URL: https://github.com/llvm/llvm-project/commit/392cba8603efc41991613d3b3faaca21fd322500
DIFF: https://github.com/llvm/llvm-project/commit/392cba8603efc41991613d3b3faaca21fd322500.diff

LOG: [flang] Handle optional TARGET associate in ASSOCIATED runtime

The TARGET argument of ASSOCIATED may be dynamically optional, in which
case ASSOCIATED(POINTER, TARGET) is equal to ASSOCIATED(TARGET).

Make the runtime argument a pointer so that it can detect and handle
arguments that are dynamically optional.

Also fix the runtime to check if TARGET base address is not null and if
its element size is not null to match the requirement of ASSOCIATED
regarding TARGET:
- if TARGET is an object: true iff [..] TARGET is not a zerosized storage sequence
- if TARGET is a POINTER: true iff [..] POINTER and TARGET are associated

Not that ASSOCIATED will also returns false if TARGET is an unallocated allocatable.
This is not described in the standard, but is a unanimous behaviour of
existing compilers.

Differential Revision: https://reviews.llvm.org/D120835

Added: 
    

Modified: 
    flang/include/flang/Runtime/pointer.h
    flang/runtime/pointer.cpp

Removed: 
    


################################################################################
diff  --git a/flang/include/flang/Runtime/pointer.h b/flang/include/flang/Runtime/pointer.h
index ea3e5b7558dad..5bb86dbf49546 100644
--- a/flang/include/flang/Runtime/pointer.h
+++ b/flang/include/flang/Runtime/pointer.h
@@ -105,7 +105,7 @@ bool RTNAME(PointerIsAssociated)(const Descriptor &);
 
 // True when the pointer is associated with a specific target.
 bool RTNAME(PointerIsAssociatedWith)(
-    const Descriptor &, const Descriptor &target);
+    const Descriptor &, const Descriptor *target);
 
 } // extern "C"
 } // namespace Fortran::runtime

diff  --git a/flang/runtime/pointer.cpp b/flang/runtime/pointer.cpp
index dd41e1f060aa0..8aebf1a603048 100644
--- a/flang/runtime/pointer.cpp
+++ b/flang/runtime/pointer.cpp
@@ -147,16 +147,22 @@ bool RTNAME(PointerIsAssociated)(const Descriptor &pointer) {
 }
 
 bool RTNAME(PointerIsAssociatedWith)(
-    const Descriptor &pointer, const Descriptor &target) {
+    const Descriptor &pointer, const Descriptor *target) {
+  if (!target) {
+    return pointer.raw().base_addr != nullptr;
+  }
+  if (!target->raw().base_addr || target->ElementBytes() == 0) {
+    return false;
+  }
   int rank{pointer.rank()};
-  if (pointer.raw().base_addr != target.raw().base_addr ||
-      pointer.ElementBytes() != target.ElementBytes() ||
-      rank != target.rank()) {
+  if (pointer.raw().base_addr != target->raw().base_addr ||
+      pointer.ElementBytes() != target->ElementBytes() ||
+      rank != target->rank()) {
     return false;
   }
   for (int j{0}; j < rank; ++j) {
     const Dimension &pDim{pointer.GetDimension(j)};
-    const Dimension &tDim{target.GetDimension(j)};
+    const Dimension &tDim{target->GetDimension(j)};
     if (pDim.Extent() != tDim.Extent() ||
         pDim.ByteStride() != tDim.ByteStride()) {
       return false;