[Fortran Support] Materialize outermost dimension for Fortran array.

- We use the outermost dimension of arrays since we need this
information to generate GPU transfers.

- In general, if we do not know the outermost dimension of the array
(because the indexing expression is non-affine, for example) then we
simply cannot generate transfer code.

- However, for Fortran arrays, we can use the Fortran array
representation which stores the dimensions of all arrays.

- This patch uses the Fortran array representation to generate code that
computes the outermost dimension size.

Differential Revision: https://reviews.llvm.org/D32967

llvm-svn: 303429

1 files changed, 9 insertions, 1 deletions

diff --git a/polly/lib/CodeGen/PPCGCodeGeneration.cpp b/polly/lib/CodeGen/PPCGCodeGeneration.cpp
index 78b5c6644c2..f0ce94d0793 100644
--- a/polly/lib/CodeGen/PPCGCodeGeneration.cpp
+++ b/polly/lib/CodeGen/PPCGCodeGeneration.cpp
@@ -2163,9 +2163,17 @@ public:
     for (unsigned i = 1; i < NumDims; ++i)
       Extent = isl_set_lower_bound_si(Extent, isl_dim_set, i, 0);
 
-    for (unsigned i = 1; i < NumDims; ++i) {
+    for (unsigned i = 0; i < NumDims; ++i) {
       isl_pw_aff *PwAff =
           const_cast<isl_pw_aff *>(Array->getDimensionSizePw(i));
+
+      // isl_pw_aff can be NULL for zero dimension. Only in the case of a
+      // Fortran array will we have a legitimate dimension.
+      if (!PwAff) {
+        assert(i == 0 && "invalid dimension isl_pw_aff for nonzero dimension");
+        continue;
+      }
+
       isl_pw_aff *Val = isl_pw_aff_from_aff(isl_aff_var_on_domain(
           isl_local_space_from_space(Array->getSpace()), isl_dim_set, i));
       PwAff = isl_pw_aff_add_dims(PwAff, isl_dim_in,