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* [Bug rtl-optimization/59446] New: loop2_doloop creates constant comparison and dead jump
@ 2013-12-10 11:19 olegendo at gcc dot gnu.org
2013-12-10 22:00 ` [Bug rtl-optimization/59446] " law at redhat dot com
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: olegendo at gcc dot gnu.org @ 2013-12-10 11:19 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59446
Bug ID: 59446
Summary: loop2_doloop creates constant comparison and dead jump
Product: gcc
Version: 4.9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: olegendo at gcc dot gnu.org
CC: law at redhat dot com
Target: sh*-*-*
After the commit that fixed PR 58640
http://gcc.gnu.org/viewcvs?rev=203463&root=gcc&view=rev
the SH specific test case gcc.target/sh/pr51244-18.c caught the following
sequence:
.L15:
mov #0,r1 // r1 = 0
tst r1,r1 // T = r1 == 0
bf.s .L7 // if (T == 0) goto .L7
add #-4,r9
The branch above never happens and is dead code.
Something causes the loop2_doloop RTL pass to create the following code, which
results in the above final code.
(code_label 108 107 109 4 2 "" [0 uses])
(note 109 108 110 4 [bb 4] NOTE_INSN_BASIC_BLOCK)
.
.
.
(insn 177 176 185 4 (set (reg:SI 304)
(plus:SI (reg:SI 305)
(const_int 1 [0x1]))) -1
(nil))
(note 185 177 180 16 [bb 16] NOTE_INSN_BASIC_BLOCK)
(insn 180 185 182 16 (set (reg:SI 306)
(plus:SI (reg/v:SI 278 [ k ])
(const_int -8 [0xfffffffffffffff8]))) -1
(nil))
(insn 182 180 183 16 (set (reg:SI 307)
(const_int -8 [0xfffffffffffffff8])) -1
(nil))
(insn 183 182 184 16 (set (reg:SI 147 t)
(ge:SI (reg:SI 306)
(reg:SI 307))) -1
(nil))
(jump_insn 184 183 181 16 (set (pc)
(if_then_else (eq (reg:SI 147 t)
(const_int 0 [0]))
(label_ref 181)
(pc))) -1
(int_list:REG_BR_PROB 0 (nil))
-> 181)
(code_label 181 184 178 14 10 "" [1 uses])
(note 178 181 186 14 [bb 14] NOTE_INSN_BASIC_BLOCK)
(insn 186 178 179 14 (set (reg:SI 304)
(const_int 1 [0x1])) -1
(nil))
(note 179 186 155 15 [bb 15] NOTE_INSN_BASIC_BLOCK)
.
.
.
.
.
.
(code_label 149 146 150 9 5 "" [1 uses])
(note 150 149 151 9 [bb 9] NOTE_INSN_BASIC_BLOCK)
(insn 151 150 152 9 (set (reg/v:SI 261 [ k ])
(plus:SI (reg/v:SI 261 [ k ])
(const_int -8 [0xfffffffffffffff8]))) pr51244-18.c:48 68
{*addsi3_compact}
(nil))
(insn 152 151 175 9 (set (reg:SI 147 t)
(ge:SI (reg/v:SI 261 [ k ])
(const_int 0 [0]))) pr51244-18.c:49 20 {cmpgesi_t}
(nil))
(jump_insn 175 152 174 9 (parallel [
(set (pc)
(if_then_else (ne:SI (reg:SI 304)
(const_int 1 [0x1]))
(label_ref 174)
(pc)))
(set (reg:SI 304)
(plus (reg:SI 304)
(const_int -1 [0xffffffffffffffff])))
(clobber (reg:SI 147 t))
]) pr51244-18.c:49 -1
(int_list:REG_BR_PROB 9700 (nil))
-> 174)
jump_insn 175 is SH's decrement-and-test pattern that is used for loops.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug rtl-optimization/59446] loop2_doloop creates constant comparison and dead jump
2013-12-10 11:19 [Bug rtl-optimization/59446] New: loop2_doloop creates constant comparison and dead jump olegendo at gcc dot gnu.org
@ 2013-12-10 22:00 ` law at redhat dot com
2013-12-10 22:17 ` olegendo at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: law at redhat dot com @ 2013-12-10 22:00 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59446
Jeffrey A. Law <law at redhat dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2013-12-10
Assignee|unassigned at gcc dot gnu.org |law at redhat dot com
Ever confirmed|0 |1
--- Comment #1 from Jeffrey A. Law <law at redhat dot com> ---
Thanks Oleg. I see what's happening and will pull together a fix.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug rtl-optimization/59446] loop2_doloop creates constant comparison and dead jump
2013-12-10 11:19 [Bug rtl-optimization/59446] New: loop2_doloop creates constant comparison and dead jump olegendo at gcc dot gnu.org
2013-12-10 22:00 ` [Bug rtl-optimization/59446] " law at redhat dot com
@ 2013-12-10 22:17 ` olegendo at gcc dot gnu.org
2013-12-11 22:15 ` law at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: olegendo at gcc dot gnu.org @ 2013-12-10 22:17 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59446
--- Comment #2 from Oleg Endo <olegendo at gcc dot gnu.org> ---
Thanks. Please let me know if I can help.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug rtl-optimization/59446] loop2_doloop creates constant comparison and dead jump
2013-12-10 11:19 [Bug rtl-optimization/59446] New: loop2_doloop creates constant comparison and dead jump olegendo at gcc dot gnu.org
2013-12-10 22:00 ` [Bug rtl-optimization/59446] " law at redhat dot com
2013-12-10 22:17 ` olegendo at gcc dot gnu.org
@ 2013-12-11 22:15 ` law at gcc dot gnu.org
2013-12-11 22:16 ` law at redhat dot com
2013-12-11 22:42 ` olegendo at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: law at gcc dot gnu.org @ 2013-12-11 22:15 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59446
--- Comment #3 from Jeffrey A. Law <law at gcc dot gnu.org> ---
Author: law
Date: Wed Dec 11 22:15:14 2013
New Revision: 205905
URL: http://gcc.gnu.org/viewcvs?rev=205905&root=gcc&view=rev
Log:
PR rtl-optimization/59446
* tree-ssa-threadupdate.c (mark_threaded_blocks): Properly
test for crossing a loop header.
Modified:
trunk/gcc/ChangeLog
trunk/gcc/tree-ssa-threadupdate.c
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug rtl-optimization/59446] loop2_doloop creates constant comparison and dead jump
2013-12-10 11:19 [Bug rtl-optimization/59446] New: loop2_doloop creates constant comparison and dead jump olegendo at gcc dot gnu.org
` (2 preceding siblings ...)
2013-12-11 22:15 ` law at gcc dot gnu.org
@ 2013-12-11 22:16 ` law at redhat dot com
2013-12-11 22:42 ` olegendo at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: law at redhat dot com @ 2013-12-11 22:16 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59446
Jeffrey A. Law <law at redhat dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution|--- |FIXED
--- Comment #4 from Jeffrey A. Law <law at redhat dot com> ---
Should be fixed on trunk now.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug rtl-optimization/59446] loop2_doloop creates constant comparison and dead jump
2013-12-10 11:19 [Bug rtl-optimization/59446] New: loop2_doloop creates constant comparison and dead jump olegendo at gcc dot gnu.org
` (3 preceding siblings ...)
2013-12-11 22:16 ` law at redhat dot com
@ 2013-12-11 22:42 ` olegendo at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: olegendo at gcc dot gnu.org @ 2013-12-11 22:42 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59446
--- Comment #5 from Oleg Endo <olegendo at gcc dot gnu.org> ---
(In reply to Jeffrey A. Law from comment #4)
> Should be fixed on trunk now.
Yep. The SH problem is also gone. Thanks!
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2013-12-11 22:42 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2013-12-10 11:19 [Bug rtl-optimization/59446] New: loop2_doloop creates constant comparison and dead jump olegendo at gcc dot gnu.org
2013-12-10 22:00 ` [Bug rtl-optimization/59446] " law at redhat dot com
2013-12-10 22:17 ` olegendo at gcc dot gnu.org
2013-12-11 22:15 ` law at gcc dot gnu.org
2013-12-11 22:16 ` law at redhat dot com
2013-12-11 22:42 ` olegendo at gcc dot gnu.org
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