Fix signal during the call to checkOpenMPLoop.

The root problem is a null pointer is accessed during the call to
checkOpenMPLoop, because loop up bound expr is an error expression
due to error diagnostic was emit early.

To fix this, in setLCDeclAndLB, setUB and setStep instead return false,
return true when LB, UB or Step contains Error, so that the checking is
stopped in checkOpenMPLoop.

Differential Revision: https://reviews.llvm.org/D107385

Author: jyu2-git

clang/lib/Sema/SemaOpenMP.cpp

@@ -7342,7 +7342,7 @@ bool OpenMPIterationSpaceChecker::setLCDeclAndLB(ValueDecl *NewLCDecl,
   // State consistency checking to ensure correct usage.
   assert(LCDecl == nullptr && LB == nullptr && LCRef == nullptr &&
          UB == nullptr && Step == nullptr && !TestIsLessOp && !TestIsStrictOp);
-  if (!NewLCDecl || !NewLB)
+  if (!NewLCDecl || !NewLB || NewLB->containsErrors())
     return true;
   LCDecl = getCanonicalDecl(NewLCDecl);
   LCRef = NewLCRefExpr;
@@ -7365,7 +7365,7 @@ bool OpenMPIterationSpaceChecker::setUB(Expr *NewUB,
   // State consistency checking to ensure correct usage.
   assert(LCDecl != nullptr && LB != nullptr && UB == nullptr &&
          Step == nullptr && !TestIsLessOp && !TestIsStrictOp);
-  if (!NewUB)
+  if (!NewUB || NewUB->containsErrors())
     return true;
   UB = NewUB;
   if (LessOp)
@@ -7380,7 +7380,7 @@ bool OpenMPIterationSpaceChecker::setUB(Expr *NewUB,
 bool OpenMPIterationSpaceChecker::setStep(Expr *NewStep, bool Subtract) {
   // State consistency checking to ensure correct usage.
   assert(LCDecl != nullptr && LB != nullptr && Step == nullptr);
-  if (!NewStep)
+  if (!NewStep || NewStep->containsErrors())
     return true;
   if (!NewStep->isValueDependent()) {
     // Check that the step is integer expression.

clang/test/OpenMP/teams_distribute_loop_messages.cpp

@@ -721,4 +721,15 @@ void test_nowait() {
   for (int i = 0; i < 16; ++i)
     ;
 }
+//expected-note@+1 {{candidate function not viable: requires single argument 'device_Id', but no arguments were provided}}
+int foo(int device_Id) {
+  return 2;
+}
+
+int main() {
+// expected-error@+1 {{no matching function for call to 'foo'}}
+  const int globalWI{ foo() };
+#pragma omp target teams distribute
+  for (int i=0 ; i<globalWI; i++) {}
+}