Added diag error message and also formatted using clang-format

Author: albus-droid

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -11700,6 +11700,8 @@ def err_omp_negative_expression_in_clause : Error<
   "argument to '%0' clause must be a %select{non-negative|strictly positive}1 integer value">;
 def err_omp_large_expression_in_clause : Error<
   "argument to '%0' clause requires a value that can be represented by a 64-bit">;
+def err_omp_unroll_factor_width_mismatch : Error<
+  "unroll factor has width %0 but the iteration variable %1 is only %2 bits wide">;
 def err_omp_not_integral : Error<
   "expression must have integral or unscoped enumeration "
   "type, not %0">;

clang/lib/Sema/SemaOpenMP.cpp

@@ -14980,13 +14980,19 @@ StmtResult SemaOpenMP::ActOnOpenMPUnrollDirective(ArrayRef<OMPClause *> Clauses,
   SourceLocation FactorLoc;
   if (Expr *FactorVal = PartialClause->getFactor();
       FactorVal && !FactorVal->containsErrors()) {
-    if (!VerifyPositiveIntegerConstantInClause(FactorVal,OMPC_partial,/*StrictlyPositive=*/true,/*SuppressExprDiags=*/false).isUsable()) {
-    return StmtError();
+    if (!VerifyPositiveIntegerConstantInClause(FactorVal, OMPC_partial,
+                                               /*StrictlyPositive=*/true,
+                                               /*SuppressExprDiags=*/false)
+             .isUsable()) {
+      return StmtError();
     }
     // Checking if Itertor Variable Type can hold the Factor Width
-    if (FactorVal->EvaluateKnownConstInt(Context).getBitWidth() > Context.getTypeSize(IVTy)) {
-          Diag(FactorVal->getExprLoc(), diag::err_omp_hint_clause_no_name);
-          return StmtError();
+    if (FactorVal->getIntegerConstantExpr(Context)->getBitWidth() >
+        Context.getTypeSize(IVTy)) {
+      Diag(FactorVal->getExprLoc(), diag::err_omp_unroll_factor_width_mismatch)
+          << FactorVal->getIntegerConstantExpr(Context)->getBitWidth() << IVTy
+          << Context.getTypeSize(IVTy);
+      return StmtError();
     }
 
     Factor = FactorVal->getIntegerConstantExpr(Context)->getZExtValue();