From: Steven G. Kargl <kargl@gcc.gnu.org>
Date: Fri, 2 Jan 2026 04:52:55 +0000 (-0800)
Subject: Fortran: Fix tab not ignored in print statement.
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=81bef9ee8d8c18c4a40d4ef67ec9b310a8a326c9;p=thirdparty%2Fgcc.git

Fortran: Fix tab not ignored in print statement.

	PR fortran/101399

gcc/fortran/ChangeLog:

	* io.cc (match_io): If the -Wtabs option is used, then Issue a
	warning for a <tab> character following a 'print' statement;
	otherwise ignore the <tab>.

gcc/testsuite/ChangeLog:

	* gfortran.dg/pr101399_1.f90: New test.
	* gfortran.dg/pr101399_2.f90: New test.
---

diff --git a/gcc/fortran/io.cc b/gcc/fortran/io.cc
index 45cac5ee572..55638c6599c 100644
--- a/gcc/fortran/io.cc
+++ b/gcc/fortran/io.cc
@@ -4223,7 +4223,21 @@ match_io (io_kind k)
       if (gfc_current_form == FORM_FREE)
 	{
 	  char c = gfc_peek_ascii_char ();
-	  if (c != ' ' && c != '*' && c != '\'' && c != '"')
+
+	  /* Issue a warning for an invalid tab in 'print<tab>*'.  After
+	     the warning is issued, consume any other whitespace and check
+	     that the next char is an *, ', or ".  */
+	  if (c == '\t')
+	    {
+	      gfc_gobble_whitespace ();
+	      c = gfc_peek_ascii_char ();
+	      if (c != '*' && c != '\'' && c != '"')
+		{
+		  m = MATCH_NO;
+		  goto cleanup;
+		}
+	    }
+	  else if (c != ' ' && c != '*' && c != '\'' && c != '"')
 	    {
 	      m = MATCH_NO;
 	      goto cleanup;
diff --git a/gcc/testsuite/gfortran.dg/pr101399_1.f90 b/gcc/testsuite/gfortran.dg/pr101399_1.f90
new file mode 100644
index 00000000000..14cf50833ec
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr101399_1.f90
@@ -0,0 +1,6 @@
+! { dg-do compile }
+! { dg-options "-O0" }
+program foo
+   ! The next statement has a tab between 'print' and '*'.
+   print	*, 'tab not always ignored'
+end program foo
diff --git a/gcc/testsuite/gfortran.dg/pr101399_2.f90 b/gcc/testsuite/gfortran.dg/pr101399_2.f90
new file mode 100644
index 00000000000..8fd203057b2
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr101399_2.f90
@@ -0,0 +1,6 @@
+! { dg-do compile }
+! { dg-options "-Wtabs" }
+program foo
+   ! The next statement has a tab between 'print' and '*'.
+   print	*, 'tab warning'  ! { dg-warning "Nonconforming tab" }
+end program foo