[DeLICM] Avoid assertion on out-of-quota.

An assertion was not prepared to be passed a nullptr because the
out-of-quota limit was exceeded.  Bail-out before the assertion
since the assertion does not apply on out-of-quote.

This fixes llvm.org/PR37477.

llvm-svn: 332488

1 files changed, 4 insertions, 0 deletions

diff --git a/polly/lib/Support/ISLTools.cpp b/polly/lib/Support/ISLTools.cpp
index 07641f43c21..c53f45f099d 100644
--- a/polly/lib/Support/ISLTools.cpp
+++ b/polly/lib/Support/ISLTools.cpp
@@ -47,6 +47,10 @@ isl::multi_aff makeShiftDimAff(isl::space Space, int Pos, int Amount) {
 /// @return { [Space1[] -> Space2[]] -> [Space2[] -> Space1[]] }
 isl::basic_map makeTupleSwapBasicMap(isl::space FromSpace1,
                                      isl::space FromSpace2) {
+  // Fast-path on out-of-quota.
+  if (!FromSpace1 || !FromSpace2)
+    return {};
+
   assert(FromSpace1.is_set());
   assert(FromSpace2.is_set());