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* [Bug c++/57066] New: std::logb(-inf) returns wrong value
@ 2013-04-25 7:01 bolero.murakami at gmail dot com
2013-04-25 8:05 ` [Bug c++/57066] [4.7/4.8/4.9 Regression] " rguenth at gcc dot gnu.org
` (9 more replies)
0 siblings, 10 replies; 11+ messages in thread
From: bolero.murakami at gmail dot com @ 2013-04-25 7:01 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57066
Bug #: 57066
Summary: std::logb(-inf) returns wrong value
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: bolero.murakami@gmail.com
auto inf = std::numeric_limits<double>::infinity();
std::cout << std::logb(-inf) << std::endl;
"-inf" is output.
it is wrong.
std::logb(-inf) should returns +inf.
> F.9.3.11 The logb functions
> - logb(±∞) returns +∞.
>From gcc-bugs-return-420917-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Thu Apr 25 07:08:12 2013
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From: "glisse at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/57064] [clarification requested] Which overload with ref-qualifier should be called?
Date: Thu, 25 Apr 2013 07:08:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?idW064
--- Comment #7 from Marc Glisse <glisse at gcc dot gnu.org> 2013-04-25 07:08:07 UTC ---
(In reply to comment #6)
> void f(A &&a)
> {
> std::move(a).p();
> }
>
> _Z1fO1A:
> .cfi_startproc
> jmp _ZNR1A1pEv@PLT #
> .cfi_endproc
>
> Then this looks like a bug in 4.8.1.
Indeed, I get s/R/O/ with 4.9.
> But then are we in agreement that a.p() in that function above should call the
> lvalue-ref overload?
Yes.
> It does make the feature sligthly less useful for me. It
> would require writing:
>
> return std::move(std::move(std::move(std::move(QString("%1 %2 %3 %4")
> .arg(42))
> .arg(47))
> .arg(-42))
> .arg(-47));
Why? You are not naming those return values, so they are still rvalues and will
use the && overload. (not sure why Qstring doesn't provide a mutating interface
for arg)
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug c++/57066] [4.7/4.8/4.9 Regression] std::logb(-inf) returns wrong value
2013-04-25 7:01 [Bug c++/57066] New: std::logb(-inf) returns wrong value bolero.murakami at gmail dot com
@ 2013-04-25 8:05 ` rguenth at gcc dot gnu.org
2013-04-25 8:41 ` mpolacek at gcc dot gnu.org
` (8 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu.org @ 2013-04-25 8:05 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57066
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Known to work| |4.1.3
Keywords| |wrong-code
Last reconfirmed| |2013-04-25
Ever Confirmed|0 |1
Summary|std::logb(-inf) returns |[4.7/4.8/4.9 Regression]
|wrong value |std::logb(-inf) returns
| |wrong value
Target Milestone|--- |4.7.4
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> 2013-04-25 08:05:04 UTC ---
/* Fold a call to builtin logb/ilogb. */
static tree
fold_builtin_logb (location_t loc, tree arg, tree rettype)
{
...
switch (value->cl)
{
case rvc_nan:
case rvc_inf:
/* If arg is Inf or NaN and we're logb, return it. */
if (TREE_CODE (rettype) == REAL_TYPE)
return fold_convert_loc (loc, rettype, arg);
is wrong for -inf. Folding introduced in 2007 thus a regression.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug c++/57066] [4.7/4.8/4.9 Regression] std::logb(-inf) returns wrong value
2013-04-25 7:01 [Bug c++/57066] New: std::logb(-inf) returns wrong value bolero.murakami at gmail dot com
2013-04-25 8:05 ` [Bug c++/57066] [4.7/4.8/4.9 Regression] " rguenth at gcc dot gnu.org
@ 2013-04-25 8:41 ` mpolacek at gcc dot gnu.org
2013-04-25 10:26 ` [Bug tree-optimization/57066] " mpolacek at gcc dot gnu.org
` (7 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2013-04-25 8:41 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57066
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |mpolacek at gcc dot gnu.org
--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> 2013-04-25 08:41:28 UTC ---
Note that at least -O is needed + -std=c++11. With -O0 it correctly prints
"inf".
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/57066] [4.7/4.8/4.9 Regression] std::logb(-inf) returns wrong value
2013-04-25 7:01 [Bug c++/57066] New: std::logb(-inf) returns wrong value bolero.murakami at gmail dot com
2013-04-25 8:05 ` [Bug c++/57066] [4.7/4.8/4.9 Regression] " rguenth at gcc dot gnu.org
2013-04-25 8:41 ` mpolacek at gcc dot gnu.org
@ 2013-04-25 10:26 ` mpolacek at gcc dot gnu.org
2013-04-25 11:47 ` mpolacek at gcc dot gnu.org
` (6 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2013-04-25 10:26 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57066
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
Component|c++ |tree-optimization
AssignedTo|unassigned at gcc dot |mpolacek at gcc dot gnu.org
|gnu.org |
--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> 2013-04-25 10:26:57 UTC ---
I may have a fix.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/57066] [4.7/4.8/4.9 Regression] std::logb(-inf) returns wrong value
2013-04-25 7:01 [Bug c++/57066] New: std::logb(-inf) returns wrong value bolero.murakami at gmail dot com
` (2 preceding siblings ...)
2013-04-25 10:26 ` [Bug tree-optimization/57066] " mpolacek at gcc dot gnu.org
@ 2013-04-25 11:47 ` mpolacek at gcc dot gnu.org
2013-04-25 13:43 ` mpolacek at gcc dot gnu.org
` (5 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2013-04-25 11:47 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57066
--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> 2013-04-25 11:47:34 UTC ---
I wonder if std::logb(-NaN) should also return +NaN.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/57066] [4.7/4.8/4.9 Regression] std::logb(-inf) returns wrong value
2013-04-25 7:01 [Bug c++/57066] New: std::logb(-inf) returns wrong value bolero.murakami at gmail dot com
` (3 preceding siblings ...)
2013-04-25 11:47 ` mpolacek at gcc dot gnu.org
@ 2013-04-25 13:43 ` mpolacek at gcc dot gnu.org
2013-04-25 15:52 ` mpolacek at gcc dot gnu.org
` (4 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2013-04-25 13:43 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57066
--- Comment #5 from Marek Polacek <mpolacek at gcc dot gnu.org> 2013-04-25 13:43:39 UTC ---
(In reply to comment #4)
> I wonder if std::logb(-NaN) should also return +NaN.
It turned out that in NaN's case it doesn't matter.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/57066] [4.7/4.8/4.9 Regression] std::logb(-inf) returns wrong value
2013-04-25 7:01 [Bug c++/57066] New: std::logb(-inf) returns wrong value bolero.murakami at gmail dot com
` (5 preceding siblings ...)
2013-04-25 15:52 ` mpolacek at gcc dot gnu.org
@ 2013-04-25 15:52 ` mpolacek at gcc dot gnu.org
2013-05-03 8:55 ` [Bug tree-optimization/57066] [4.7/4.8 " mpolacek at gcc dot gnu.org
` (2 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2013-04-25 15:52 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57066
--- Comment #6 from Marek Polacek <mpolacek at gcc dot gnu.org> 2013-04-25 15:52:16 UTC ---
Author: mpolacek
Date: Thu Apr 25 15:51:57 2013
New Revision: 198308
URL: http://gcc.gnu.org/viewcvs?rev=198308&root=gcc&view=rev
Log:
PR tree-optimization/57066
* builtins.c (fold_builtin_logb): Return +Inf for -Inf.
* gcc.dg/torture/builtin-logb-1.c: Adjust testcase.
Modified:
trunk/gcc/ChangeLog
trunk/gcc/builtins.c
trunk/gcc/testsuite/ChangeLog
trunk/gcc/testsuite/gcc.dg/torture/builtin-logb-1.c
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/57066] [4.7/4.8/4.9 Regression] std::logb(-inf) returns wrong value
2013-04-25 7:01 [Bug c++/57066] New: std::logb(-inf) returns wrong value bolero.murakami at gmail dot com
` (4 preceding siblings ...)
2013-04-25 13:43 ` mpolacek at gcc dot gnu.org
@ 2013-04-25 15:52 ` mpolacek at gcc dot gnu.org
2013-04-25 15:52 ` mpolacek at gcc dot gnu.org
` (3 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2013-04-25 15:52 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57066
--- Comment #7 from Marek Polacek <mpolacek at gcc dot gnu.org> 2013-04-25 15:52:45 UTC ---
Fixed on trunk so far, will backport to 4.7/4.8 later on.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/57066] [4.7/4.8 Regression] std::logb(-inf) returns wrong value
2013-04-25 7:01 [Bug c++/57066] New: std::logb(-inf) returns wrong value bolero.murakami at gmail dot com
` (6 preceding siblings ...)
2013-04-25 15:52 ` mpolacek at gcc dot gnu.org
@ 2013-05-03 8:55 ` mpolacek at gcc dot gnu.org
2013-05-03 8:59 ` mpolacek at gcc dot gnu.org
2013-05-03 8:59 ` mpolacek at gcc dot gnu.org
9 siblings, 0 replies; 11+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2013-05-03 8:55 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57066
--- Comment #8 from Marek Polacek <mpolacek at gcc dot gnu.org> 2013-05-03 08:55:26 UTC ---
Author: mpolacek
Date: Fri May 3 08:55:08 2013
New Revision: 198570
URL: http://gcc.gnu.org/viewcvs?rev=198570&root=gcc&view=rev
Log:
PR tree-optimization/57066
* builtins.c (fold_builtin_logb): Return +Inf for -Inf.
* gcc.dg/torture/builtin-logb-1.c: Adjust testcase.
Modified:
branches/gcc-4_8-branch/gcc/ChangeLog
branches/gcc-4_8-branch/gcc/builtins.c
branches/gcc-4_8-branch/gcc/testsuite/ChangeLog
branches/gcc-4_8-branch/gcc/testsuite/gcc.dg/torture/builtin-logb-1.c
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/57066] [4.7/4.8 Regression] std::logb(-inf) returns wrong value
2013-04-25 7:01 [Bug c++/57066] New: std::logb(-inf) returns wrong value bolero.murakami at gmail dot com
` (7 preceding siblings ...)
2013-05-03 8:55 ` [Bug tree-optimization/57066] [4.7/4.8 " mpolacek at gcc dot gnu.org
@ 2013-05-03 8:59 ` mpolacek at gcc dot gnu.org
2013-05-03 8:59 ` mpolacek at gcc dot gnu.org
9 siblings, 0 replies; 11+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2013-05-03 8:59 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57066
--- Comment #9 from Marek Polacek <mpolacek at gcc dot gnu.org> 2013-05-03 08:59:30 UTC ---
Author: mpolacek
Date: Fri May 3 08:59:14 2013
New Revision: 198571
URL: http://gcc.gnu.org/viewcvs?rev=198571&root=gcc&view=rev
Log:
PR tree-optimization/57066
* builtins.c (fold_builtin_logb): Return +Inf for -Inf.
* gcc.dg/torture/builtin-logb-1.c: Adjust testcase.
Modified:
branches/gcc-4_7-branch/gcc/ChangeLog
branches/gcc-4_7-branch/gcc/builtins.c
branches/gcc-4_7-branch/gcc/testsuite/ChangeLog
branches/gcc-4_7-branch/gcc/testsuite/gcc.dg/torture/builtin-logb-1.c
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug tree-optimization/57066] [4.7/4.8 Regression] std::logb(-inf) returns wrong value
2013-04-25 7:01 [Bug c++/57066] New: std::logb(-inf) returns wrong value bolero.murakami at gmail dot com
` (8 preceding siblings ...)
2013-05-03 8:59 ` mpolacek at gcc dot gnu.org
@ 2013-05-03 8:59 ` mpolacek at gcc dot gnu.org
9 siblings, 0 replies; 11+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2013-05-03 8:59 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57066
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
--- Comment #10 from Marek Polacek <mpolacek at gcc dot gnu.org> 2013-05-03 08:59:42 UTC ---
Fixed.
^ permalink raw reply [flat|nested] 11+ messages in thread
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2013-04-25 7:01 [Bug c++/57066] New: std::logb(-inf) returns wrong value bolero.murakami at gmail dot com
2013-04-25 8:05 ` [Bug c++/57066] [4.7/4.8/4.9 Regression] " rguenth at gcc dot gnu.org
2013-04-25 8:41 ` mpolacek at gcc dot gnu.org
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