From: Harald Anlauf <anlauf@gmx.de>
Date: Wed, 25 Nov 2020 19:20:44 +0000 (+0100)
Subject: PR fortran/85796 - Floating point exception with implied do
X-Git-Tag: releases/gcc-10.3.0~580
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=67e7f56b6795023dbf59d27e200668b04ce63c3a;p=thirdparty%2Fgcc.git

PR fortran/85796 - Floating point exception with implied do

Catch invalid step=0 in implied do loop within data statements.

gcc/fortran/ChangeLog:

	PR fortran/85796
	* resolve.c (traverse_data_list): Fix copy&paste errors; catch
	step=0 in implied do loop.

gcc/testsuite/ChangeLog:

	PR fortran/85796
	* gfortran.dg/pr85796.f90: New test.

(cherry picked from commit 94172dc7091a2c6b2d2f99857de77c607fac3935)
---

diff --git a/gcc/fortran/resolve.c b/gcc/fortran/resolve.c
index 0d9908e912f3..0eb650bce616 100644
--- a/gcc/fortran/resolve.c
+++ b/gcc/fortran/resolve.c
@@ -16271,7 +16271,7 @@ traverse_data_list (gfc_data_variable *var, locus *where)
       || end->expr_type != EXPR_CONSTANT)
     {
       gfc_error ("end of implied-do loop at %L could not be "
-		 "simplified to a constant value", &start->where);
+		 "simplified to a constant value", &end->where);
       retval = false;
       goto cleanup;
     }
@@ -16279,7 +16279,14 @@ traverse_data_list (gfc_data_variable *var, locus *where)
       || step->expr_type != EXPR_CONSTANT)
     {
       gfc_error ("step of implied-do loop at %L could not be "
-		 "simplified to a constant value", &start->where);
+		 "simplified to a constant value", &step->where);
+      retval = false;
+      goto cleanup;
+    }
+  if (mpz_cmp_si (step->value.integer, 0) == 0)
+    {
+      gfc_error ("step of implied-do loop at %L shall not be zero",
+		 &step->where);
       retval = false;
       goto cleanup;
     }
diff --git a/gcc/testsuite/gfortran.dg/pr85796.f90 b/gcc/testsuite/gfortran.dg/pr85796.f90
new file mode 100644
index 000000000000..78683787fbb3
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr85796.f90
@@ -0,0 +1,8 @@
+! { dg-do compile }
+! PR fortran/85796 - Floating point exception with implied do in data statement
+
+program p
+  implicit none
+  integer :: i, j, x(2,2)
+  data ((x(i,j),i=1,2,j-1),j=1,2) /3*789/ ! { dg-error "step of implied-do loop" }
+end