[flang-commits] [flang] 71d5a94 - [flang] Don't fold SIZE()/SHAPE() into expression referencing optional dummy arguments

[Peter Klausler via flang-commits]

Author: Peter Klausler
Date: 2023-05-31T08:57:18-07:00
New Revision: 71d5a94985c9569467c1ef8a62b8b326ee2036a6

URL: https://github.com/llvm/llvm-project/commit/71d5a94985c9569467c1ef8a62b8b326ee2036a6
DIFF: https://github.com/llvm/llvm-project/commit/71d5a94985c9569467c1ef8a62b8b326ee2036a6.diff

LOG: [flang] Don't fold SIZE()/SHAPE() into expression referencing optional dummy arguments

When computing the shape of an expression at compilation time as part of
folding an intrinsic function like SIZE(), don't create an expression that
increases a dependence on the presence of an optional dummy argument.

Differential Revision: https://reviews.llvm.org/D151737

Added: 
    flang/test/Evaluate/elem-shape.f90

Modified: 
    flang/lib/Evaluate/shape.cpp

Removed: 
    


################################################################################
diff  --git a/flang/lib/Evaluate/shape.cpp b/flang/lib/Evaluate/shape.cpp
index 6f6baaec2b61e..c7dcb1c672979 100644
--- a/flang/lib/Evaluate/shape.cpp
+++ b/flang/lib/Evaluate/shape.cpp
@@ -805,9 +805,19 @@ auto GetShapeHelper::operator()(const ProcedureRef &call) const -> Result {
   if (call.Rank() == 0) {
     return ScalarShape();
   } else if (call.IsElemental()) {
-    for (const auto &arg : call.arguments()) {
-      if (arg && arg->Rank() > 0) {
-        return (*this)(*arg);
+    // Use the shape of an actual array argument associated with a
+    // non-OPTIONAL dummy object argument.
+    if (context_) {
+      if (auto chars{characteristics::Procedure::FromActuals(
+              call.proc(), call.arguments(), *context_)}) {
+        std::size_t j{0};
+        for (const auto &arg : call.arguments()) {
+          if (arg && arg->Rank() > 0 && j < chars->dummyArguments.size() &&
+              !chars->dummyArguments[j].IsOptional()) {
+            return (*this)(*arg);
+          }
+          ++j;
+        }
       }
     }
     return ScalarShape();

diff  --git a/flang/test/Evaluate/elem-shape.f90 b/flang/test/Evaluate/elem-shape.f90
new file mode 100644
index 0000000000000..623c833274cb3
--- /dev/null
+++ b/flang/test/Evaluate/elem-shape.f90
@@ -0,0 +1,16 @@
+! RUN: %flang_fc1 -fdebug-unparse %s 2>&1 | FileCheck %s
+! Ensure that optional arguments aren't used to fold SIZE() or SHAPE()
+module m
+ contains
+  subroutine sub(x,y)
+    real :: x(:), y(:)
+    optional x
+    !CHECK: PRINT *, int(size(y,dim=1,kind=8),kind=4)
+    print *, size(f(x,y))
+  end
+  elemental function f(x,y)
+    real, intent(in) :: x, y
+    optional x
+    f = y
+  end
+end