[Bug middle-end/43419] gcc replaces pow(x, 0.5) by sqrt(x), invalid when x is -0

[jackie.rosen at hushmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43419

Jackie Rosen jackie.rosen at hushmail dot com changed:

   What|Removed |Added

 CC||jackie.rosen at hushmail dot 
com

--- Comment #10 from Jackie Rosen jackie.rosen at hushmail dot com ---
*** Bug 260998 has been marked as a duplicate of this bug. ***
Seen from the domain http://volichat.com
Page where seen: http://volichat.com/adult-chat-rooms
Marked for reference. Resolved as fixed @bugzilla.

[Bug middle-end/43419] gcc replaces pow(x, 0.5) by sqrt(x), invalid when x is -0

[hjl dot tools at gmail dot com]

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hjl dot tools at gmail dot com changed:

   What|Removed |Added

  Known to fail||4.3.4
  Known to work||4.4.4 4.5.0
   Target Milestone|--- |4.5.0
Version|unknown |4.5.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43419

[Bug middle-end/43419] gcc replaces pow(x, 0.5) by sqrt(x), invalid when x is -0

[jakub at gcc dot gnu dot org]

--- Comment #8 from jakub at gcc dot gnu dot org  2010-03-22 14:58 ---
Subject: Bug 43419

Author: jakub
Date: Mon Mar 22 14:58:00 2010
New Revision: 157631

URL: http://gcc.gnu.org/viewcvs?root=gccview=revrev=157631
Log:
Backport from mainline:
2010-03-18  Michael Matz  m...@suse.de

PR middle-end/43419
* builtins.c (expand_builtin_pow): Don't transform pow(x, 0.5)
into sqrt(x) if we need to preserve signed zeros.

* gcc.dg/pr43419.c: New testcase.

Added:
branches/gcc-4_4-branch/gcc/testsuite/gcc.dg/pr43419.c
Modified:
branches/gcc-4_4-branch/gcc/ChangeLog
branches/gcc-4_4-branch/gcc/builtins.c
branches/gcc-4_4-branch/gcc/testsuite/ChangeLog


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43419

[Bug middle-end/43419] gcc replaces pow(x, 0.5) by sqrt(x), invalid when x is -0

[mikpe at it dot uu dot se]

--- Comment #9 from mikpe at it dot uu dot se  2010-03-22 16:02 ---
This bug also affects 4.3 branch. The upstream patch applies Ok and fixes it.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43419

[Bug middle-end/43419] gcc replaces pow(x, 0.5) by sqrt(x), invalid when x is -0

[vincent at vinc17 dot org]

--- Comment #1 from vincent at vinc17 dot org  2010-03-18 14:33 ---
If I understand correctly, the bug appears with:

r119248 | rguenth | 2006-11-27 12:38:42 +0100 (Mon, 27 Nov 2006) | 10 lines

2006-11-27  Richard Guenther  rguent...@suse.de

PR middle-end/25620
* builtins.c (expand_builtin_pow): Optimize non integer valued
constant exponents using sqrt or cbrt if possible.  Always fall back
to expanding via optabs.

* gcc.target/i386/pow-1.c: New testcase.
* gcc.dg/builtins-58.c: Likewise.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43419

[Bug middle-end/43419] gcc replaces pow(x, 0.5) by sqrt(x), invalid when x is -0

[matz at gcc dot gnu dot org]

--- Comment #2 from matz at gcc dot gnu dot org  2010-03-18 14:35 ---
Mine.


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matz at gcc dot gnu dot org changed:

   What|Removed |Added

 AssignedTo|unassigned at gcc dot gnu   |matz at gcc dot gnu dot org
   |dot org |
 Status|UNCONFIRMED |ASSIGNED
 Ever Confirmed|0   |1
   Last reconfirmed|-00-00 00:00:00 |2010-03-18 14:35:38
   date||


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43419

[Bug middle-end/43419] gcc replaces pow(x, 0.5) by sqrt(x), invalid when x is -0

[dominiq at lps dot ens dot fr]

--- Comment #3 from dominiq at lps dot ens dot fr  2010-03-18 14:41 ---
While you are looking at this part, you may have to check that a similar
problem does not exist when converting x*sqrt(x) to pow(w,1.5) and so on.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43419

[Bug middle-end/43419] gcc replaces pow(x, 0.5) by sqrt(x), invalid when x is -0

[matz at gcc dot gnu dot org]

--- Comment #4 from matz at gcc dot gnu dot org  2010-03-18 14:48 ---
I checked, and these and similar transformations are always guarded by
flag_unsafe_math_optimizations, so we should be fine, unless I missed a case
of course.  If you notice one, please create a bug report.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43419

[Bug middle-end/43419] gcc replaces pow(x, 0.5) by sqrt(x), invalid when x is -0

[rguenth at gcc dot gnu dot org]

--- Comment #5 from rguenth at gcc dot gnu dot org  2010-03-18 15:31 ---
Looks like we need to guard this with HONOR_SIGNED_ZEROS.


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rguenth at gcc dot gnu dot org changed:

   What|Removed |Added

   Keywords||wrong-code


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43419

[Bug middle-end/43419] gcc replaces pow(x, 0.5) by sqrt(x), invalid when x is -0

[matz at gcc dot gnu dot org]

--- Comment #6 from matz at gcc dot gnu dot org  2010-03-18 16:08 ---
Subject: Bug 43419

Author: matz
Date: Thu Mar 18 16:07:53 2010
New Revision: 157543

URL: http://gcc.gnu.org/viewcvs?root=gccview=revrev=157543
Log:
PR middle-end/43419
* builtins.c (expand_builtin_pow): Don't transform pow(x, 0.5)
into sqrt(x) if we need to preserve signed zeros.

testsuite/
* gcc.dg/pr43419.c: New testcase.

Added:
trunk/gcc/testsuite/gcc.dg/pr43419.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/builtins.c
trunk/gcc/testsuite/ChangeLog


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43419

[Bug middle-end/43419] gcc replaces pow(x, 0.5) by sqrt(x), invalid when x is -0

[matz at gcc dot gnu dot org]

--- Comment #7 from matz at gcc dot gnu dot org  2010-03-18 16:47 ---
Fixed.


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matz at gcc dot gnu dot org changed:

   What|Removed |Added

 Status|ASSIGNED|RESOLVED
 Resolution||FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43419