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

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2016-09-04  Thomas Koenig  <tkoenig@gcc.gnu.org>

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

2016-09-04  Thomas Koenig  <tkoenig@gcc.gnu.org>

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

From-SVN: r239977
This commit is contained in:
Thomas Koenig 2016-09-04 16:17:55 +00:00
parent abb62d32a1
commit d6598cf719
3 changed files with 45 additions and 2 deletions
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19
gcc/fortran/frontend-passes.c
View file

@ -164,19 +164,34 @@ realloc_string_callback (gfc_code **c, int *walk_subtrees ATTRIBUTE_UNUSED,
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;
@ -190,7 +205,7 @@ realloc_string_callback (gfc_code **c, int *walk_subtrees ATTRIBUTE_UNUSED,
current_code = c;
inserted_block = NULL;
changed_statement = NULL;
n = create_var (expr2, "trim");
n = create_var (expr2, "realloc_string");
co->expr2 = n;
return 0;
}

14
gcc/testsuite/gfortran.dg/dependency_47.f90 Normal file
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@ -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" } }

14
gcc/testsuite/gfortran.dg/dependency_49.f90 Normal file
View file

@ -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" } }