[Flang] Solved issue with inline compiler directive (#143699)

Issue was with pointer passing.

Fixes #139297

Author: EbinJose2002

flang/lib/Parser/prescan.cpp

@@ -557,7 +557,7 @@ bool Prescanner::MustSkipToEndOfLine() const {
     return true; // skip over ignored columns in right margin (73:80)
   } else if (*at_ == '!' && !inCharLiteral_ &&
       (!inFixedForm_ || tabInCurrentLine_ || column_ != 6)) {
-    return !IsCompilerDirectiveSentinel(at_);
+    return !IsCompilerDirectiveSentinel(at_ + 1);
   } else {
     return false;
   }

flang/test/Parser/inline-directives.f90

@@ -0,0 +1,29 @@
+! RUN: %flang_fc1 -fdebug-unparse %s 2>&1 | FileCheck %s
+
+! Test that checks whether compiler directives can be inlined without mistaking it as comment.
+
+module m
+contains
+#define MACRO(X)  subroutine func1(X); real(2) :: X; !dir$ ignore_tkr(d) X; end subroutine func1;
+MACRO(foo)
+
+!CHECK: SUBROUTINE func1 (foo)
+!CHECK: !DIR$ IGNORE_TKR (d) foo
+!CHECK: END SUBROUTINE func1
+
+  subroutine func2(foo)
+    real(2) :: foo; !dir$ ignore_tkr(d) foo;
+  end subroutine func2
+
+!CHECK: SUBROUTINE func2 (foo)
+!CHECK: !DIR$ IGNORE_TKR (d) foo
+!CHECK: END SUBROUTINE func2
+
+  subroutine func3(foo)
+    real(2) :: foo; !dir$ ignore_tkr(d) foo; end subroutine func3;
+
+!CHECK: SUBROUTINE func3 (foo)
+!CHECK: !DIR$ IGNORE_TKR (d) foo
+!CHECK: END SUBROUTINE func3
+
+end module