[OpenMP][FIX] Invalidate the SPMDCompatibilityTracker explicitly

Before SPMDzation it was sufficient to add an incompatible instruction
to the SPMDCompatibilityTracker. However, now adding instructions means
they need guarding. As calls cannot be guarded in general we need to
explicitly prevent SPMD mode.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D115158

Author: jhuber6

llvm/lib/Transforms/IPO/OpenMPOpt.cpp

@@ -4010,6 +4010,7 @@ struct AAKernelInfoCallSite : AAKernelInfo {
       break;
     case OMPRTL___kmpc_omp_task:
       // We do not look into tasks right now, just give up.
+      SPMDCompatibilityTracker.indicatePessimisticFixpoint();
       SPMDCompatibilityTracker.insert(&CB);
       ReachedUnknownParallelRegions.insert(&CB);
       break;
@@ -4020,6 +4021,7 @@ struct AAKernelInfoCallSite : AAKernelInfo {
     default:
       // Unknown OpenMP runtime calls cannot be executed in SPMD-mode,
       // generally. However, they do not hide parallel regions.
+      SPMDCompatibilityTracker.indicatePessimisticFixpoint();
       SPMDCompatibilityTracker.insert(&CB);
       break;
     }
@@ -4079,6 +4081,7 @@ struct AAKernelInfoCallSite : AAKernelInfo {
         SPMDCompatibilityTracker.insert(&CB);
       break;
     default:
+      SPMDCompatibilityTracker.indicatePessimisticFixpoint();
       SPMDCompatibilityTracker.insert(&CB);
     }