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* [Bug middle-end/27800] extra temprorary created when gimplifying return
[not found] <bug-27800-4@http.gcc.gnu.org/bugzilla/>
@ 2021-07-24 5:35 ` pinskia at gcc dot gnu.org
2023-02-06 12:16 ` rguenth at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-07-24 5:35 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=27800
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |compile-time-hog,
| |memory-hog
Last reconfirmed|2006-05-29 21:13:57 |2021-7-23
Severity|normal |enhancement
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug middle-end/27800] extra temprorary created when gimplifying return
[not found] <bug-27800-4@http.gcc.gnu.org/bugzilla/>
2021-07-24 5:35 ` [Bug middle-end/27800] extra temprorary created when gimplifying return pinskia at gcc dot gnu.org
@ 2023-02-06 12:16 ` rguenth at gcc dot gnu.org
2024-02-20 10:46 ` rguenth at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 5+ messages in thread
From: rguenth at gcc dot gnu.org @ 2023-02-06 12:16 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=27800
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Dan Nicolaescu from comment #1)
> An even simpler example which occurs quite frequently in programs:
>
> int jjj (int a){ return bar (a); }
>
> jjj (a)
> {
> int D.1891;
> int D.1892;
>
> D.1892 = bar (a);
> D.1891 = D.1892;
> return D.1891;
> }
That one is meanwhile fixed.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug middle-end/27800] extra temprorary created when gimplifying return
[not found] <bug-27800-4@http.gcc.gnu.org/bugzilla/>
2021-07-24 5:35 ` [Bug middle-end/27800] extra temprorary created when gimplifying return pinskia at gcc dot gnu.org
2023-02-06 12:16 ` rguenth at gcc dot gnu.org
@ 2024-02-20 10:46 ` rguenth at gcc dot gnu.org
2024-05-07 12:20 ` cvs-commit at gcc dot gnu.org
2024-05-07 12:20 ` rguenth at gcc dot gnu.org
4 siblings, 0 replies; 5+ messages in thread
From: rguenth at gcc dot gnu.org @ 2024-02-20 10:46 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=27800
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
Assignee|unassigned at gcc dot gnu.org |rguenth at gcc dot gnu.org
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Note this is done on purpose, possibly to better handle functions with multiple
returns.
A fix is probably in gimplification of the MODIFY_EXPR
D.2774 = a != 0 ? b : c
where gimplify_cond_expr isn't told it can re-use the LHS as temporary.
That means special-casing this COND_EXPR RHS in gimplify_modify_expr_rhs
which already handles the non-register type case. It could be extended
to cover all cases which then generates the smaller
int iii (int a, int b, int c)
{
int D.2774;
if (a != 0) goto <D.2775>; else goto <D.2776>;
<D.2775>:
D.2774 = b;
goto <D.2777>;
<D.2776>:
D.2774 = c;
<D.2777>:
return D.2774;
}
diff --git a/gcc/gimplify.cc b/gcc/gimplify.cc
index 76221f7637d..b48c43f1471 100644
--- a/gcc/gimplify.cc
+++ b/gcc/gimplify.cc
@@ -5985,7 +5985,7 @@ gimplify_modify_expr_rhs (tree *expr_p, tree *from_p,
tree *to_p,
down into the branches. This is mandatory for ADDRESSABLE types,
since we cannot generate temporaries for such, but it saves a
copy in other cases as well. */
- if (!is_gimple_reg_type (TREE_TYPE (*from_p)))
+ if (1)
{
/* This code should mirror the code in gimplify_cond_expr. */
enum tree_code code = TREE_CODE (*expr_p);
or to cases where is_gimple_reg (*to_p).
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug middle-end/27800] extra temprorary created when gimplifying return
[not found] <bug-27800-4@http.gcc.gnu.org/bugzilla/>
` (2 preceding siblings ...)
2024-02-20 10:46 ` rguenth at gcc dot gnu.org
@ 2024-05-07 12:20 ` cvs-commit at gcc dot gnu.org
2024-05-07 12:20 ` rguenth at gcc dot gnu.org
4 siblings, 0 replies; 5+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2024-05-07 12:20 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=27800
--- Comment #5 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Richard Biener <rguenth@gcc.gnu.org>:
https://gcc.gnu.org/g:bed6ec161be8c5ca2f24195900ce3c9b81c3e141
commit r15-276-gbed6ec161be8c5ca2f24195900ce3c9b81c3e141
Author: Richard Biener <rguenther@suse.de>
Date: Tue Feb 20 11:47:03 2024 +0100
middle-end/27800 - avoid unnecessary temporary during gimplification
This avoids a tempoary when gimplifying reg = a ? b : c, re-using
the LHS of an assignment if that's a register.
PR middle-end/27800
* gimplify.cc (gimplify_modify_expr_rhs): For a COND_EXPR
avoid a temporary from gimplify_cond_expr when the LHS is
a register by pushing the assignment into the COND_EXPR arms.
* gcc.dg/pr27800.c: New testcase.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug middle-end/27800] extra temprorary created when gimplifying return
[not found] <bug-27800-4@http.gcc.gnu.org/bugzilla/>
` (3 preceding siblings ...)
2024-05-07 12:20 ` cvs-commit at gcc dot gnu.org
@ 2024-05-07 12:20 ` rguenth at gcc dot gnu.org
4 siblings, 0 replies; 5+ messages in thread
From: rguenth at gcc dot gnu.org @ 2024-05-07 12:20 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=27800
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |15.0
Resolution|--- |FIXED
Status|ASSIGNED |RESOLVED
--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
I consider this fixed as far as possible now.
^ permalink raw reply [flat|nested] 5+ messages in thread
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2021-07-24 5:35 ` [Bug middle-end/27800] extra temprorary created when gimplifying return pinskia at gcc dot gnu.org
2023-02-06 12:16 ` rguenth at gcc dot gnu.org
2024-02-20 10:46 ` rguenth at gcc dot gnu.org
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