backport: re PR fortran/71902 (Unneeded temporary on reallocatable character assignment)

2016-10-31  Thomas Koenig  <tkoenig@gcc.gnu.org>

	Backport from trunk
	PR fortran/71902
	* frontend-passes.c (realloc_string_callback): Also check for the
	lhs being deferred.  Name temporary variable "realloc_string".

2016-10-31  Thomas Koenig  <tkoenig@gcc.gnu.org>

	Backport from trunk
	PR fortran/71902
	* gfortran.dg/dependency_47.f90:  New test.
	* gfortran.dg/dependency_49.f90:  New test.

From-SVN: r241732

diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog
index 1f812f78c95daac7dc5f713fcaa0c0d255490c63..0cb900e9e92084ab0b917634aeb7225cc8ad5644 100644 (file)
--- a/gcc/fortran/ChangeLog
+++ b/gcc/fortran/ChangeLog
@@ -1,3 +1,10 @@
+2016-11-01  Thomas Koenig  <tkoenig@gcc.gnu.org>
+
+       Backport from trunk
+       PR fortran/71902
+       * frontend-passes.c (realloc_string_callback): Also check for the
+       lhs being deferred.  Name temporary variable "realloc_string".
+
 2016-10-24  Thomas Koenig  <tkoenig@gcc.gnu.org>
 
        Backport from trunk

diff --git a/gcc/fortran/frontend-passes.c b/gcc/fortran/frontend-passes.c
index 38d7a100e749a71168d6dd3db8a6ddd7d75a83e2..c051cc09d0aec9d74792ce71a0651a7dc6066334 100644 (file)
--- a/gcc/fortran/frontend-passes.c
+++ b/gcc/fortran/frontend-passes.c
@@ -144,19 +144,34 @@ realloc_string_callback (gfc_code **c, int *walk_subtrees,
   gfc_expr *expr1, *expr2;
   gfc_code *co = *c;
   gfc_expr *n;
+  gfc_ref *ref;
+  bool found_substr;
 
   if (co->op != EXEC_ASSIGN)
     return 0;
 
   expr1 = co->expr1;
   if (expr1->ts.type != BT_CHARACTER || expr1->rank != 0
-      || !expr1->symtree->n.sym->attr.allocatable)
+      || !gfc_expr_attr(expr1).allocatable
+      || !expr1->ts.deferred)
     return 0;
 
   expr2 = gfc_discard_nops (co->expr2);
   if (expr2->expr_type != EXPR_VARIABLE)
     return 0;
 
+  found_substr = false;
+  for (ref = expr2->ref; ref; ref = ref->next)
+    {
+      if (ref->type == REF_SUBSTRING)
+       {
+         found_substr = true;
+         break;
+       }
+    }
+  if (!found_substr)
+    return 0;
+
   if (!gfc_check_dependency (expr1, expr2, true))
     return 0;
 

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index cf77a64be9d9fd85eb440ff48448e9e58abd8429..e34697c2ad4f3120c02a33cbf14c80bf78e7f28e 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2016-10-31  Thomas Koenig  <tkoenig@gcc.gnu.org>
+
+       Backport from trunk
+       PR fortran/71902
+       * gfortran.dg/dependency_47.f90:  New test.
+       * gfortran.dg/dependency_49.f90:  New test.
+
 2016-10-31  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
 
        Backport from trunk

diff --git a/gcc/testsuite/gfortran.dg/dependency_47.f90 b/gcc/testsuite/gfortran.dg/dependency_47.f90
new file mode 100644 (file)
index 0000000..4888771
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/dependency_47.f90
@@ -0,0 +1,14 @@
+! { dg-do compile }
+! Make sure there is only one instance of a temporary variable here.
+! { dg-options "-fdump-tree-original" }
+
+SUBROUTINE prtdata(ilen)
+  INTEGER :: ilen
+  character(len=ilen), allocatable :: cline(:)
+  allocate(cline(2))
+  cline(1) = 'a'
+  cline(1)(2:3) = cline(1)(1:2)
+  cline(2) = cline(1)
+  print *,c
+END SUBROUTINE prtdata
+! { dg-final { scan-tree-dump-not "__var_" "original" } }

diff --git a/gcc/testsuite/gfortran.dg/dependency_49.f90 b/gcc/testsuite/gfortran.dg/dependency_49.f90
new file mode 100644 (file)
index 0000000..73d517e
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/dependency_49.f90
@@ -0,0 +1,14 @@
+! { dg-do compile }
+! { dg-options "-fdump-tree-original" }
+! PR fortran/71902 - make sure that component references are followed
+! for dependency analysis.
+program main
+  type foo
+     character(len=:), allocatable :: x
+  end type foo
+  type(foo) :: a
+  a%x = 'asdf'
+  a%x = a%x(2:3)
+  print *,a%x
+end program main
+! { dg-final { scan-tree-dump-times "__var_1" 4 "original" } }