[Polly][Isl] Removing nullptr constructor from C++ bindings. NFC.

[Polly][Isl] Removing nullptr constructor from C++ bindings. NFC.

This is part of an effort to reduce the differences between the custom C++ bindings used right now by polly in `lib/External/isl/include/isl/isl-noxceptions.h` and the official isl C++ interface.

Changes made:
 - Removed `std::nullptr_t` constructor from all the classes in the isl C++ bindings.
 - `isl-noexceptions.h` has been generated by this https://github.com/patacca/isl/commit/a7e00bea38f251a4bcf5c2c6ce5fa7ee5f661528

Reviewed By: Meinersbur

Differential Revision: https://reviews.llvm.org/D103751

1 files changed, 2 insertions, 2 deletions

diff --git a/polly/unittests/DeLICM/DeLICMTest.cpp b/polly/unittests/DeLICM/DeLICMTest.cpp
index 3e6b6f0..eaa37ee 100644
--- a/polly/unittests/DeLICM/DeLICMTest.cpp
+++ b/polly/unittests/DeLICM/DeLICMTest.cpp
@@ -80,13 +80,13 @@ typedef struct {
 
 isl::union_set parseSetOrNull(isl_ctx *Ctx, const char *Str) {
   if (!Str)
-    return nullptr;
+    return {};
   return isl::union_set(Ctx, Str);
 }
 
 isl::union_map parseMapOrNull(isl_ctx *Ctx, const char *Str) {
   if (!Str)
-    return nullptr;
+    return {};
   return isl::union_map(Ctx, Str);
 }