2011-12-05 Thomas Koenig <tkoenig@gcc.gnu.org>

	PR fortran/51338
	* dependency.c (are_identical_variables):  Handle case where
	end fields of substring references are NULL.

2011-12-05  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/51338
	* gfortran.dg/assumed_charlen_substring_1.f90:  New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@182024 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog
index 4b553db..4b23c58 100644 (file)
--- a/gcc/fortran/ChangeLog
+++ b/gcc/fortran/ChangeLog
@@ -1,3 +1,9 @@
+2011-12-05  Thomas Koenig  <tkoenig@gcc.gnu.org>
+
+       PR fortran/51338
+       * dependency.c (are_identical_variables):  Handle case where
+       end fields of substring references are NULL.
+
 2011-12-04  Tobias Burnus  <burnus@net-b.de>
 
        PR fortran/51383
@@ -12,7 +18,7 @@
        * class.c (gfc_build_class_symbol): Handle
        attr.select_type_temporary.
 
-2011-12-03  Tobias Burnus  <burnus@net-b.de>                                                                                                           
+2011-12-03  Tobias Burnus  <burnus@net-b.de>
 
        PR fortran/50684
        * check.c (variable_check): Fix intent(in) check.

diff --git a/gcc/fortran/dependency.c b/gcc/fortran/dependency.c
index fd7fa73..96c4e5f 100644 (file)
--- a/gcc/fortran/dependency.c
+++ b/gcc/fortran/dependency.c
@@ -173,9 +173,19 @@ are_identical_variables (gfc_expr *e1, gfc_expr *e2)
          break;
 
        case REF_SUBSTRING:
-         if (gfc_dep_compare_expr (r1->u.ss.start, r2->u.ss.start) != 0
-             || gfc_dep_compare_expr (r1->u.ss.end, r2->u.ss.end) != 0)
+         if (gfc_dep_compare_expr (r1->u.ss.start, r2->u.ss.start) != 0)
            return false;
+
+         /* If both are NULL, the end length compares equal, because we
+            are looking at the same variable. This can only happen for
+            assumed- or deferred-length character arguments.  */ 
+
+         if (r1->u.ss.end == NULL && r2->u.ss.end == NULL)
+           break;
+
+         if (gfc_dep_compare_expr (r1->u.ss.end, r2->u.ss.end) != 0)
+           return false;
+         
          break;
 
        default:

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 180c8c3..bf505ce 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2011-12-05  Thomas Koenig  <tkoenig@gcc.gnu.org>
+
+       PR fortran/51338
+       * gfortran.dg/assumed_charlen_substring_1.f90:  New test.
+
 2011-12-05  Richard Sandiford  <rdsandiford@googlemail.com>
 
        * g++.dg/debug/pr46338.C: Add dg-require-profiling.

diff --git a/gcc/testsuite/gfortran.dg/assumed_charlen_substring_1.f90 b/gcc/testsuite/gfortran.dg/assumed_charlen_substring_1.f90
new file mode 100644 (file)
index 0000000..b4697dc
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/assumed_charlen_substring_1.f90
@@ -0,0 +1,10 @@
+! { dg-do compile }
+! { dg-options "-O -fdump-tree-original" }
+! PR 51338 - this used to ICE.
+! Original test case by Bud Davis.
+subroutine foo(a,b)
+  character(len=*) :: a
+  if (a(1:) /= a(1:)) call do_not_use
+end subroutine foo
+! { dg-final { scan-tree-dump-times "do_not_use" 0 "original" } }
+! { dg-final { cleanup-tree-dump "original" } }