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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/111542] [11/12/13/14 Regression] (a==0)&(b==0) into `(a|b) == 0` optimization sometimes gets in the way of other optimizations
Date: Sat, 23 Sep 2023 20:23:50 +0000 [thread overview]
Message-ID: <bug-111542-4-FesdWmfdDQ@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-111542-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111542
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #2)
> Match pattern:
> ```
> (for bitop (bit_ior bit_and)
> cmp1 (eq ne )
> cmp2 (ne eq )
> (simplify
> (bitop:c
> (cmp1 @1 integer_zerop)
> (cmp2 (bit_ior:c @0 @1) integer_zerop))
> { constant_boolean_node (bitop == BIT_IOR_EXPR, type); }))
> ```
But this breaks generic-match building of the function:
tree
generic_simplify_92 (location_t ARG_UNUSED (loc), const tree ARG_UNUSED (type),
tree ARG_UNUSED (_p0), tree ARG_UNUSED (_p1), tree *captures,
const enum tree_code ARG_UNUSED (bitop),
const enum tree_code ARG_UNUSED (cmp1),
const enum tree_code ARG_UNUSED (cmp2))
{
const bool debug_dump = dump_file && (dump_flags & TDF_FOLDING);
if (TREE_SIDE_EFFECTS (_p0)) goto next_after_fail192;
if (TREE_SIDE_EFFECTS (_p1)) goto next_after_fail192;
if (UNLIKELY (!dbg_cnt (match))) goto next_after_fail192;
{
tree _r;
_r = constant_boolean_node (bitop == BIT_IOR_EXPR, type);
if (UNLIKELY (debug_dump)) generic_dump_logs ("match.pd", 136, __FILE__,
__LINE__, true);
return _r;
}
next_after_fail192:;
return NULL_TREE;
}
captures is not used .
I guess I could check TREE_SIDE_EFFECTS on @0/@1 to workaround that issue.
Like so:
```
(for bitop (bit_ior bit_and)
cmp1 (eq ne )
cmp2 (ne eq )
(simplify
(bitop:c
(cmp1 @1 integer_zerop)
(cmp2 (bit_ior:c @0 @1) integer_zerop))
(if (GIMPLE || (!TREE_SIDE_EFFECTS (@0)
&& !TREE_SIDE_EFFECTS (@1)))
{ constant_boolean_node (bitop == BIT_IOR_EXPR, type); })))
```
I had assumed genmatch would generate that code that would use @0/@1 if they
had side effects. Maybe because I match @0 twice, it assumed we would be using
the captures (I have not looked though).
next prev parent reply other threads:[~2023-09-23 20:23 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-22 18:51 [Bug tree-optimization/111542] New: [11/12/13/14 Regression] pinskia at gcc dot gnu.org
2023-09-22 18:54 ` [Bug tree-optimization/111542] " pinskia at gcc dot gnu.org
2023-09-22 18:55 ` [Bug tree-optimization/111542] [11/12/13/14 Regression] (a==0)&(b==0) into `(a|b) == 0` optimization sometimes gets in the way of other optimizations pinskia at gcc dot gnu.org
2023-09-23 20:14 ` pinskia at gcc dot gnu.org
2023-09-23 20:23 ` pinskia at gcc dot gnu.org [this message]
2023-10-17 13:00 ` rguenth at gcc dot gnu.org
2024-05-07 7:42 ` [Bug tree-optimization/111542] [11/12/13/14/15 " rguenth at gcc dot gnu.org
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