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* [Bug tree-optimization/46027] New: (unsignedtype1)(unsignedtype2)(unsignedtype1_var) not changed into unsignedtype1_var & NNN when sizeof(type1) > sizeof(type2)
@ 2010-10-14 18:55 pinskia at gcc dot gnu.org
2010-10-14 18:56 ` [Bug tree-optimization/46027] " pinskia at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: pinskia at gcc dot gnu.org @ 2010-10-14 18:55 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46027
Summary: (unsignedtype1)(unsignedtype2)(unsignedtype1_var) not
changed into unsignedtype1_var & NNN when
sizeof(type1) > sizeof(type2)
Product: gcc
Version: 4.5.0
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: tree-optimization
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: pinskia@gcc.gnu.org
Take:
typedef unsigned type1;
typedef unsigned char type2;
type1 t;
void f(type1 tt)
{
t = (type2)tt;
}
--- CUT ---
In .optimized we have:
D.2687_2 = (unsigned char) tt_1(D);
t.0_3 = (type1) D.2687_2;
t = t.0_3;
--- CUT ---
This is done on the RTL level, well I think it uses (zero_extend(subreg)) as
the conical form (at least on big endian targets). Using &0xFF here would be
faster and less memory usage and might be able to optimize more.
Here is a testcase which shows where we can optimize more if we do this:
typedef unsigned type1;
typedef unsigned char type2;
type1 t;
void f(type1 tt)
{
type2 t1 = t;
type1 t2 = t1;
t = t2 & 0xFF;
}
void f1(type1 tt)
{
type1 t2 = t & 0xff;
t = t2 & 0xFF;
}
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/46027] (unsignedtype1)(unsignedtype2)(unsignedtype1_var) not changed into unsignedtype1_var & NNN when sizeof(type1) > sizeof(type2)
2010-10-14 18:55 [Bug tree-optimization/46027] New: (unsignedtype1)(unsignedtype2)(unsignedtype1_var) not changed into unsignedtype1_var & NNN when sizeof(type1) > sizeof(type2) pinskia at gcc dot gnu.org
@ 2010-10-14 18:56 ` pinskia at gcc dot gnu.org
2010-10-19 0:29 ` pinskia at gcc dot gnu.org
2011-11-29 23:42 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu.org @ 2010-10-14 18:56 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46027
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2010.10.14 18:56:06
AssignedTo|unassigned at gcc dot |pinskia at gcc dot gnu.org
|gnu.org |
Ever Confirmed|0 |1
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> 2010-10-14 18:56:06 UTC ---
I am working on this. I found this while looking into some 4.3 SRA produced
trees.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/46027] (unsignedtype1)(unsignedtype2)(unsignedtype1_var) not changed into unsignedtype1_var & NNN when sizeof(type1) > sizeof(type2)
2010-10-14 18:55 [Bug tree-optimization/46027] New: (unsignedtype1)(unsignedtype2)(unsignedtype1_var) not changed into unsignedtype1_var & NNN when sizeof(type1) > sizeof(type2) pinskia at gcc dot gnu.org
2010-10-14 18:56 ` [Bug tree-optimization/46027] " pinskia at gcc dot gnu.org
@ 2010-10-19 0:29 ` pinskia at gcc dot gnu.org
2011-11-29 23:42 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu.org @ 2010-10-19 0:29 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46027
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> 2010-10-19 00:29:18 UTC ---
Here is a full testcase:
typedef unsigned type1;
typedef unsigned char type2;
type1 t;
void f(type1 tt)
{
type2 t1 = t;
type1 t2 = t1;
t = t2 & 0xFF;
}
void f2(type1 tt)
{
type1 t2 = (type2)t;
t = t2 & 0xFF;
}
void f1(type1 tt)
{
type1 t2 = t & 0xff;
t = t2 & 0xFF;
}
---- CUT ----
Currently f does not get optimized after my patch. f1 is optimized before my
patch and f2 is optimized afterwards. f requires some kind of forward
prop/tree combining to do the work.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/46027] (unsignedtype1)(unsignedtype2)(unsignedtype1_var) not changed into unsignedtype1_var & NNN when sizeof(type1) > sizeof(type2)
2010-10-14 18:55 [Bug tree-optimization/46027] New: (unsignedtype1)(unsignedtype2)(unsignedtype1_var) not changed into unsignedtype1_var & NNN when sizeof(type1) > sizeof(type2) pinskia at gcc dot gnu.org
2010-10-14 18:56 ` [Bug tree-optimization/46027] " pinskia at gcc dot gnu.org
2010-10-19 0:29 ` pinskia at gcc dot gnu.org
@ 2011-11-29 23:42 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu.org @ 2011-11-29 23:42 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46027
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
Target Milestone|--- |4.7.0
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> 2011-11-29 23:28:40 UTC ---
Fixed on the trunk by:
2011-05-10 Richard Guenther <rguenther@suse.de>
* tree-ssa-forwprop.c (combine_conversions): Pattern-match
a series of conversions and apply foldings similar to what
fold-const does.
(tree_ssa_forward_propagate_single_use_vars): Call it.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2011-11-29 23:28 UTC | newest]
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2010-10-14 18:55 [Bug tree-optimization/46027] New: (unsignedtype1)(unsignedtype2)(unsignedtype1_var) not changed into unsignedtype1_var & NNN when sizeof(type1) > sizeof(type2) pinskia at gcc dot gnu.org
2010-10-14 18:56 ` [Bug tree-optimization/46027] " pinskia at gcc dot gnu.org
2010-10-19 0:29 ` pinskia at gcc dot gnu.org
2011-11-29 23:42 ` pinskia at gcc dot gnu.org
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