From: Elizebeth Punnoose <elizebeth.punnoose@hpe.com>
Date: Thu, 1 Dec 2016 23:11:35 +0000 (+0000)
Subject: re PR fortran/77505 (Negative character length not treated as LEN=0)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=90ee6453b254cd77819bc30d9d13a3c9828fd1c5;p=gcc.git

re PR fortran/77505 (Negative character length not treated as LEN=0)

2016-12-01  Elizebeth Punnoose  <elizebeth.punnoose@hpe.com>

	PR fortran/77505
	* trans-array.c (trans_array_constructor): Treat negative character
	length as LEN = 0.


2016-12-01  Elizebeth Punnoose  <elizebeth.punnoose@hpe.com>

	PR fortran/77505
	* gfortran.dg/char_length_20.f90: New test.
	* gfortran.dg/char_length_21.f90: Ditto.

From-SVN: r243143
---

diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog
index d4103927100..20a9f2e2ba7 100644
--- a/gcc/fortran/ChangeLog
+++ b/gcc/fortran/ChangeLog
@@ -1,3 +1,9 @@
+2016-12-01  Elizebeth Punnoose  <elizebeth.punnoose@hpe.com>
+
+	PR fortran/77505
+	* trans-array.c (trans_array_constructor): Treat negative character
+	length as LEN = 0.
+
 2016-12-01  Steven G. Kargl  <kargl@gcc.gnu.org>
 
 	PR fortran/78279
diff --git a/gcc/fortran/trans-array.c b/gcc/fortran/trans-array.c
index 803462a4ec8..ac90a4ba188 100644
--- a/gcc/fortran/trans-array.c
+++ b/gcc/fortran/trans-array.c
@@ -2226,6 +2226,8 @@ trans_array_constructor (gfc_ss * ss, locus * where)
   gfc_ss_info *ss_info;
   gfc_expr *expr;
   gfc_ss *s;
+  tree neg_len;
+  char *msg;
 
   /* Save the old values for nested checking.  */
   old_first_len = first_len;
@@ -2271,6 +2273,29 @@ trans_array_constructor (gfc_ss * ss, locus * where)
 	  gfc_conv_expr_type (&length_se, expr->ts.u.cl->length,
 			      gfc_charlen_type_node);
 	  ss_info->string_length = length_se.expr;
+
+	  /* Check if the character length is negative.  If it is, then
+	     set LEN = 0.  */
+	  neg_len = fold_build2_loc (input_location, LT_EXPR,
+				     boolean_type_node, ss_info->string_length,
+				     build_int_cst (gfc_charlen_type_node, 0));
+	  /* Print a warning if bounds checking is enabled.  */
+	  if (gfc_option.rtcheck & GFC_RTCHECK_BOUNDS)
+	    {
+	      msg = xasprintf ("Negative character length treated as LEN = 0");
+	      gfc_trans_runtime_check (false, true, neg_len, &length_se.pre,
+				       where, msg);
+	      free (msg);
+	    }
+
+	  ss_info->string_length
+	    = fold_build3_loc (input_location, COND_EXPR,
+			       gfc_charlen_type_node, neg_len,
+			       build_int_cst (gfc_charlen_type_node, 0),
+			       ss_info->string_length);
+	  ss_info->string_length = gfc_evaluate_now (ss_info->string_length,
+						     &length_se.pre);
+
 	  gfc_add_block_to_block (&outer_loop->pre, &length_se.pre);
 	  gfc_add_block_to_block (&outer_loop->post, &length_se.post);
 	}
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 321a48a8eab..dcbdf565208 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2016-12-01  Elizebeth Punnoose  <elizebeth.punnoose@hpe.com>
+
+	PR fortran/77505
+	* gfortran.dg/char_length_20.f90: New test.
+	* gfortran.dg/char_length_21.f90: Ditto.
+
 2016-12-01  Steven G. Kargl  <kargl@gcc.gnu.org>
 
 	PR fortran/78279
diff --git a/gcc/testsuite/gfortran.dg/char_length_20.f90 b/gcc/testsuite/gfortran.dg/char_length_20.f90
new file mode 100644
index 00000000000..38a19c5b0ba
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/char_length_20.f90
@@ -0,0 +1,13 @@
+! { dg-do run }
+! { dg-options "-fcheck=bounds" }
+program rabbithole
+   implicit none
+   character(len=:), allocatable :: text_block(:)
+   integer i, ii
+   character(len=10) :: cten='abcdefghij'
+   character(len=20) :: ctwenty='abcdefghijabcdefghij'
+   ii = -6
+   text_block=[ character(len=ii) :: cten, ctwenty ]
+   if (any(len_trim(text_block) /= 0)) call abort
+end program rabbithole
+! { dg-output "At line 10 of file .*char_length_20.f90.*Fortran runtime warning: Negative character length treated as LEN = 0" }
diff --git a/gcc/testsuite/gfortran.dg/char_length_21.f90 b/gcc/testsuite/gfortran.dg/char_length_21.f90
new file mode 100644
index 00000000000..76b7e8e28e8
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/char_length_21.f90
@@ -0,0 +1,11 @@
+! { dg-do run }
+program rabbithole
+   implicit none
+   character(len=:), allocatable :: text_block(:)
+   integer i, ii
+   character(len=10) :: cten='abcdefghij'
+   character(len=20) :: ctwenty='abcdefghijabcdefghij'
+   ii = -6
+   text_block = [character(len=ii) :: cten, ctwenty]
+   if (any(len_trim(text_block) /= 0)) call abort
+end program rabbithole