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* [Bug tree-optimization/14495] [tree-ssa] Propagate range info into a switch statement
[not found] <bug-14495-5009@http.gcc.gnu.org/bugzilla/>
@ 2006-04-20 10:58 ` wouter dot vermaelen at pi dot be
2007-04-13 9:31 ` rguenth at gcc dot gnu dot org
` (4 subsequent siblings)
5 siblings, 0 replies; 11+ messages in thread
From: wouter dot vermaelen at pi dot be @ 2006-04-20 10:58 UTC (permalink / raw)
To: gcc-bugs
------- Comment #5 from wouter dot vermaelen at pi dot be 2006-04-20 10:58 -------
I think something similar happens for the following code.
int f(int a) {
switch (a & 7) {
case 0: return 2;
case 1: return 3;
case 2: return 5;
case 3: return 7;
case 4: return 11;
case 5: return 13;
case 6: return 17;
case 7: return 19;
}
}
Part of the generated code looks like this:
movl 8(%ebp), %eax
andl $7, %eax
cmpl $7, %eax
jbe .L15
popl %ebp
ret
.p2align 4,,15
.L15:
jmp *.L11(,%eax,4)
The test for values bigger than 7 is clearly not needed here.
I don't know much about compiler technologie, but maybe this specific case is
easier to solve with some peephole optimization?
I have seen real code (Z80 emulator or HQ2x scaler algorithm) that does a
switch on a unsigned char and handles all 256 cases. Code like that would
benefit from this optimization.
Thanks.
--
wouter dot vermaelen at pi dot be changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |wouter dot vermaelen at pi
| |dot be
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14495
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/14495] [tree-ssa] Propagate range info into a switch statement
[not found] <bug-14495-5009@http.gcc.gnu.org/bugzilla/>
2006-04-20 10:58 ` [Bug tree-optimization/14495] [tree-ssa] Propagate range info into a switch statement wouter dot vermaelen at pi dot be
@ 2007-04-13 9:31 ` rguenth at gcc dot gnu dot org
2007-04-17 13:05 ` patchapp at dberlin dot org
` (3 subsequent siblings)
5 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2007-04-13 9:31 UTC (permalink / raw)
To: gcc-bugs
------- Comment #6 from rguenth at gcc dot gnu dot org 2007-04-13 10:31 -------
I have a patch to handle the ONE edge case.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
AssignedTo|unassigned at gcc dot gnu |rguenth at gcc dot gnu dot
|dot org |org
Status|NEW |ASSIGNED
Last reconfirmed|2006-03-05 17:19:18 |2007-04-13 10:31:07
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14495
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/14495] [tree-ssa] Propagate range info into a switch statement
[not found] <bug-14495-5009@http.gcc.gnu.org/bugzilla/>
2006-04-20 10:58 ` [Bug tree-optimization/14495] [tree-ssa] Propagate range info into a switch statement wouter dot vermaelen at pi dot be
2007-04-13 9:31 ` rguenth at gcc dot gnu dot org
@ 2007-04-17 13:05 ` patchapp at dberlin dot org
2008-04-02 12:53 ` rguenth at gcc dot gnu dot org
` (2 subsequent siblings)
5 siblings, 0 replies; 11+ messages in thread
From: patchapp at dberlin dot org @ 2007-04-17 13:05 UTC (permalink / raw)
To: gcc-bugs
------- Comment #7 from patchapp at dberlin dot org 2007-04-17 14:05 -------
Subject: Bug number PR14495
A patch for this bug has been added to the patch tracker.
The mailing list url for the patch is
http://gcc.gnu.org/ml/gcc-patches/2007-04/msg01072.html
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14495
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/14495] [tree-ssa] Propagate range info into a switch statement
[not found] <bug-14495-5009@http.gcc.gnu.org/bugzilla/>
` (2 preceding siblings ...)
2007-04-17 13:05 ` patchapp at dberlin dot org
@ 2008-04-02 12:53 ` rguenth at gcc dot gnu dot org
2008-04-02 12:55 ` rguenth at gcc dot gnu dot org
2008-04-02 12:56 ` rguenth at gcc dot gnu dot org
5 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2008-04-02 12:53 UTC (permalink / raw)
To: gcc-bugs
------- Comment #8 from rguenth at gcc dot gnu dot org 2008-04-02 12:52 -------
Subject: Bug 14495
Author: rguenth
Date: Wed Apr 2 12:51:37 2008
New Revision: 133834
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=133834
Log:
2008-04-02 Richard Guenther <rguenther@suse.de>
PR tree-optimization/14495
* tree-vrp.c (vrp_visit_cond_stmt): Do not handle
SWITCH_EXPR here ...
(vrp_visit_switch_stmt): ... but here (new function).
(find_case_label_index): New helper function.
(vrp_visit_stmt): Dispatch to vrp_visit_switch_stmt.
* gcc.dg/tree-ssa/vrp40.c: New testcase.
Added:
trunk/gcc/testsuite/gcc.dg/tree-ssa/vrp40.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/testsuite/ChangeLog
trunk/gcc/tree-vrp.c
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14495
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/14495] [tree-ssa] Propagate range info into a switch statement
[not found] <bug-14495-5009@http.gcc.gnu.org/bugzilla/>
` (3 preceding siblings ...)
2008-04-02 12:53 ` rguenth at gcc dot gnu dot org
@ 2008-04-02 12:55 ` rguenth at gcc dot gnu dot org
2008-04-02 12:56 ` rguenth at gcc dot gnu dot org
5 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2008-04-02 12:55 UTC (permalink / raw)
To: gcc-bugs
------- Comment #9 from rguenth at gcc dot gnu dot org 2008-04-02 12:54 -------
Subject: Bug 14495
Author: rguenth
Date: Wed Apr 2 12:54:08 2008
New Revision: 133835
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=133835
Log:
2008-04-02 Richard Guenther <rguenther@suse.de>
PR tree-optimization/14495
PR tree-optimization/34793
* tree-vrp.c (struct switch_update): New structure.
(to_remove_edges, to_update_switch_stmts): New VECs.
(simplify_switch_using_ranges): New function. Remove not taken
case labels and edges.
(simplify_stmt_using_ranges): Call it.
(identify_jump_threads): Mark edges we have queued for removal
so we don't thread them.
(execute_vrp): Remove edges queued for removal, update SWITCH_STMT
case label vector.
* tree-cfg.c (group_case_labels): Deal with missing default label.
(tree_verify_flow_info): Allow missing default label.
* stmt.c (emit_case_bit_tests): Deal with NULL default_label.
(emit_case_nodes): Likewise.
(expand_case): Do not rely on the default label to be present.
* expr.c (try_casesi): Deal with NULL default_label.
(do_tablejump): Likewise.
* gcc.dg/tree-ssa/vrp41.c: New testcase.
* gcc.dg/tree-ssa/vrp42.c: Likewise.
Added:
trunk/gcc/testsuite/gcc.dg/tree-ssa/vrp41.c
trunk/gcc/testsuite/gcc.dg/tree-ssa/vrp42.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/expr.c
trunk/gcc/stmt.c
trunk/gcc/testsuite/ChangeLog
trunk/gcc/tree-cfg.c
trunk/gcc/tree-vrp.c
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14495
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/14495] [tree-ssa] Propagate range info into a switch statement
[not found] <bug-14495-5009@http.gcc.gnu.org/bugzilla/>
` (4 preceding siblings ...)
2008-04-02 12:55 ` rguenth at gcc dot gnu dot org
@ 2008-04-02 12:56 ` rguenth at gcc dot gnu dot org
5 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2008-04-02 12:56 UTC (permalink / raw)
To: gcc-bugs
------- Comment #10 from rguenth at gcc dot gnu dot org 2008-04-02 12:55 -------
Fixed.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
Target Milestone|--- |4.4.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14495
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/14495] [tree-ssa] Propagate range info into a switch statement
[not found] <20040309003513.14495.kazu@gcc.gnu.org>
@ 2005-09-10 18:10 ` pinskia at gcc dot gnu dot org
0 siblings, 0 replies; 11+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-09-10 18:10 UTC (permalink / raw)
To: gcc-bugs
--
Bug 14495 depends on bug 18373, which changed state.
Bug 18373 Summary: [meta-bug] VRP Value Range Propagation
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18373
What |Old Value |New Value
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |FIXED
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14495
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/14495] [tree-ssa] Propagate range info into a switch statement
2004-03-09 0:35 [Bug optimization/14495] New: " kazu at cs dot umass dot edu
` (2 preceding siblings ...)
2005-05-08 18:10 ` pinskia at gcc dot gnu dot org
@ 2005-06-03 13:55 ` dnovillo at gcc dot gnu dot org
3 siblings, 0 replies; 11+ messages in thread
From: dnovillo at gcc dot gnu dot org @ 2005-06-03 13:55 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From dnovillo at gcc dot gnu dot org 2005-06-03 13:55 -------
The issue is that the propagator engine does not implement the concept of
multiway branches taking some edges. It supports ONE, NONE or ALL.
Frankly, I'm not at all convinced that this is worth handling. But if we were
to handle it, the place to fix is the propagator engine.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14495
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/14495] [tree-ssa] Propagate range info into a switch statement
2004-03-09 0:35 [Bug optimization/14495] New: " kazu at cs dot umass dot edu
2004-05-24 15:57 ` [Bug tree-optimization/14495] " pinskia at gcc dot gnu dot org
2005-04-24 11:52 ` pinskia at gcc dot gnu dot org
@ 2005-05-08 18:10 ` pinskia at gcc dot gnu dot org
2005-06-03 13:55 ` dnovillo at gcc dot gnu dot org
3 siblings, 0 replies; 11+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-05-08 18:10 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-05-08 18:10 -------
I think the issue is that we don't simulate anything besides COND_EXPR.
--
What |Removed |Added
----------------------------------------------------------------------------
CC| |dnovillo at gcc dot gnu dot
| |org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14495
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/14495] [tree-ssa] Propagate range info into a switch statement
2004-03-09 0:35 [Bug optimization/14495] New: " kazu at cs dot umass dot edu
2004-05-24 15:57 ` [Bug tree-optimization/14495] " pinskia at gcc dot gnu dot org
@ 2005-04-24 11:52 ` pinskia at gcc dot gnu dot org
2005-05-08 18:10 ` pinskia at gcc dot gnu dot org
2005-06-03 13:55 ` dnovillo at gcc dot gnu dot org
3 siblings, 0 replies; 11+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-04-24 11:52 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-04-24 11:52 -------
VRP does not remove this for some reason even though we have now enough information to do so:
a_2: [100, 200]
switch (a_2)
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14495
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/14495] [tree-ssa] Propagate range info into a switch statement
2004-03-09 0:35 [Bug optimization/14495] New: " kazu at cs dot umass dot edu
@ 2004-05-24 15:57 ` pinskia at gcc dot gnu dot org
2005-04-24 11:52 ` pinskia at gcc dot gnu dot org
` (2 subsequent siblings)
3 siblings, 0 replies; 11+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-05-24 15:57 UTC (permalink / raw)
To: gcc-bugs
--
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|3.5.0 |---
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14495
^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2008-04-02 12:56 UTC | newest]
Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
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[not found] <bug-14495-5009@http.gcc.gnu.org/bugzilla/>
2006-04-20 10:58 ` [Bug tree-optimization/14495] [tree-ssa] Propagate range info into a switch statement wouter dot vermaelen at pi dot be
2007-04-13 9:31 ` rguenth at gcc dot gnu dot org
2007-04-17 13:05 ` patchapp at dberlin dot org
2008-04-02 12:53 ` rguenth at gcc dot gnu dot org
2008-04-02 12:55 ` rguenth at gcc dot gnu dot org
2008-04-02 12:56 ` rguenth at gcc dot gnu dot org
[not found] <20040309003513.14495.kazu@gcc.gnu.org>
2005-09-10 18:10 ` pinskia at gcc dot gnu dot org
2004-03-09 0:35 [Bug optimization/14495] New: " kazu at cs dot umass dot edu
2004-05-24 15:57 ` [Bug tree-optimization/14495] " pinskia at gcc dot gnu dot org
2005-04-24 11:52 ` pinskia at gcc dot gnu dot org
2005-05-08 18:10 ` pinskia at gcc dot gnu dot org
2005-06-03 13:55 ` dnovillo at gcc dot gnu dot org
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