* [patch, fortran] Fix PR 43072
@ 2019-01-15 21:58 Thomas Koenig
2019-01-15 22:11 ` Steve Kargl
0 siblings, 1 reply; 3+ messages in thread
From: Thomas Koenig @ 2019-01-15 21:58 UTC (permalink / raw)
To: fortran, gcc-patches
[-- Attachment #1: Type: text/plain, Size: 671 bytes --]
Hello world,
the attached patch fixes a missed optimization where a substring equal
in length to the original variable currently leads to an unneeded
temporary.
Regression-tested. OK for trunk?
Regards
Thomas
2019-01-15 Thomas Koenig <tkoenig@gcc.gnu.org>
PR fortran/43072
* resolve.c (resolve_array_ref): Add equal_length argument; set it
if the length of the substring equals that of the orignal
variable.
(resolve_ref): Remove the substring if it is equal in length
length to the original variable, unless it is an EXPR_SUBSTRING).
2019-01-15 Thomas Koenig <tkoenig@gcc.gnu.org>
PR fortran/43072
* gfortran.dg/actual_array_substr_3.f90: New test.
[-- Attachment #2: p2.diff --]
[-- Type: text/x-patch, Size: 1896 bytes --]
Index: resolve.c
===================================================================
--- resolve.c (Revision 267903)
+++ resolve.c (Arbeitskopie)
@@ -4873,7 +4873,7 @@ resolve_array_ref (gfc_array_ref *ar)
static bool
-resolve_substring (gfc_ref *ref)
+resolve_substring (gfc_ref *ref, bool *equal_length)
{
int k = gfc_validate_kind (BT_INTEGER, gfc_charlen_int_kind, false);
@@ -4944,6 +4944,13 @@ static bool
&ref->u.ss.end->where);
return false;
}
+ /* If the substring has the same length as the original
+ variable, the reference itself can be deleted. */
+
+ if (ref->u.ss.length != NULL
+ && compare_bound (ref->u.ss.end, ref->u.ss.length->length) == CMP_EQ
+ && compare_bound_int (ref->u.ss.start, 1) == CMP_EQ)
+ *equal_length = true;
}
return true;
@@ -5037,7 +5044,8 @@ static bool
resolve_ref (gfc_expr *expr)
{
int current_part_dimension, n_components, seen_part_dimension;
- gfc_ref *ref;
+ gfc_ref *ref, **prev;
+ bool equal_length;
for (ref = expr->ref; ref; ref = ref->next)
if (ref->type == REF_ARRAY && ref->u.ar.as == NULL)
@@ -5046,7 +5054,8 @@ resolve_ref (gfc_expr *expr)
break;
}
- for (ref = expr->ref; ref; ref = ref->next)
+
+ for (ref = expr->ref, prev = &expr->ref; ref; prev = &ref->next, ref = ref->next)
switch (ref->type)
{
case REF_ARRAY:
@@ -5059,8 +5068,19 @@ resolve_ref (gfc_expr *expr)
break;
case REF_SUBSTRING:
- if (!resolve_substring (ref))
+ equal_length = false;
+ if (!resolve_substring (ref, &equal_length))
return false;
+
+ if (expr->expr_type != EXPR_SUBSTRING && equal_length)
+ {
+ /* Remove the reference and move the charlen, if any. */
+ *prev = ref->next;
+ ref->next = NULL;
+ expr->ts.u.cl = ref->u.ss.length;
+ ref->u.ss.length = NULL;
+ gfc_free_ref_list (ref);
+ }
break;
}
[-- Attachment #3: actual_array_substr_3.f90 --]
[-- Type: text/x-fortran, Size: 342 bytes --]
! { dg-do compile }
! { dg-additional-options "-fdump-tree-original" }
! PR 43072 - no temporary needed because the substring
! is of equal length to the string.
subroutine foo2
implicit none
external foo
character(len=20) :: str(2) = '1234567890'
call foo(str(:)(1:20))
end
! { dg-final { scan-tree-dump-not "memmove" "original" } }
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [patch, fortran] Fix PR 43072
2019-01-15 21:58 [patch, fortran] Fix PR 43072 Thomas Koenig
@ 2019-01-15 22:11 ` Steve Kargl
2019-01-15 22:37 ` Thomas Koenig
0 siblings, 1 reply; 3+ messages in thread
From: Steve Kargl @ 2019-01-15 22:11 UTC (permalink / raw)
To: Thomas Koenig; +Cc: fortran, gcc-patches
On Tue, Jan 15, 2019 at 10:58:33PM +0100, Thomas Koenig wrote:
>
> the attached patch fixes a missed optimization where a substring equal
> in length to the original variable currently leads to an unneeded
> temporary.
>
> Regression-tested. OK for trunk?
Yes. See below.
>
> 2019-01-15 Thomas Koenig <tkoenig@gcc.gnu.org>
>
> PR fortran/43072
> * resolve.c (resolve_array_ref): Add equal_length argument; set it
> if the length of the substring equals that of the orignal
> variable.
> (resolve_ref): Remove the substring if it is equal in length
> length to the original variable, unless it is an EXPR_SUBSTRING).
in length length?
--
Steve
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [patch, fortran] Fix PR 43072
2019-01-15 22:11 ` Steve Kargl
@ 2019-01-15 22:37 ` Thomas Koenig
0 siblings, 0 replies; 3+ messages in thread
From: Thomas Koenig @ 2019-01-15 22:37 UTC (permalink / raw)
To: sgk; +Cc: fortran, gcc-patches
Hi Steve,
> On Tue, Jan 15, 2019 at 10:58:33PM +0100, Thomas Koenig wrote:
>>
>> the attached patch fixes a missed optimization where a substring equal
>> in length to the original variable currently leads to an unneeded
>> temporary.
>>
>> Regression-tested. OK for trunk?
>
> Yes. See below.
Thanks.
>>
>> 2019-01-15 Thomas Koenig <tkoenig@gcc.gnu.org>
>>
>> PR fortran/43072
>> * resolve.c (resolve_array_ref): Add equal_length argument; set it
>> if the length of the substring equals that of the orignal
>> variable.
>> (resolve_ref): Remove the substring if it is equal in length
>> length to the original variable, unless it is an EXPR_SUBSTRING).
>
> in length length?
Fixed in the commit.
Regards
Thomas
^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-01-15 21:58 [patch, fortran] Fix PR 43072 Thomas Koenig
2019-01-15 22:11 ` Steve Kargl
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