[clang] Move Diags.isIgnored() check below faster checks (#141084)

Because this check is relatively slow and the others aren't as much.


http://llvm-compile-time-tracker.com/compare.php?from=4a158f675be7fd1b3763bf39980d801db89744f8&to=886a8fab041ff7574d54cccddbc1a9b968c1bb58&stat=instructions:u

Author: tbaederr

clang/lib/Sema/SemaChecking.cpp

@@ -11745,10 +11745,6 @@ static void CheckImplicitArgumentConversions(Sema &S, CallExpr *TheCall,
 
 static void DiagnoseNullConversion(Sema &S, Expr *E, QualType T,
                                    SourceLocation CC) {
-  if (S.Diags.isIgnored(diag::warn_impcast_null_pointer_to_integer,
-                        E->getExprLoc()))
-    return;
-
   // Don't warn on functions which have return type nullptr_t.
   if (isa<CallExpr>(E))
     return;
@@ -11765,6 +11761,10 @@ static void DiagnoseNullConversion(Sema &S, Expr *E, QualType T,
       T->isMemberPointerType() || !T->isScalarType() || T->isNullPtrType())
     return;
 
+  if (S.Diags.isIgnored(diag::warn_impcast_null_pointer_to_integer,
+                        E->getExprLoc()))
+    return;
+
   SourceLocation Loc = E->getSourceRange().getBegin();
 
   // Venture through the macro stacks to get to the source of macro arguments.