[Bug middle-end/45273] New: [4.4/4.5/4.6 Regression] The compiler depends on the host double (-fprofile-corection only)

[Bug middle-end/45273] New: [4.4/4.5/4.6 Regression] The compiler depends on the host double (-fprofile-corection only)

[pinskia at gcc dot gnu dot org]

While looking into PR 45272, I noticed it depends on the host double which is
wrong, we should not depend on that.  The main reason is because different
hosts could produce slightly different results depending on the behavior of
float.

Oh Second mcf_sqrt depends on IEEE FP single precision.


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           Summary: [4.4/4.5/4.6 Regression] The compiler depends on the
                    host double (-fprofile-corection only)
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org
OtherBugsDependingO 45272
             nThis:


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45273

[Bug middle-end/45273] [4.4/4.5/4.6 Regression] The compiler depends on the host double (-fprofile-corection only)

[pinskia at gcc dot gnu dot org]

-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.4.5


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45273

[Bug middle-end/45273] [4.4/4.5/4.6 Regression] The compiler depends on the host double (-fprofile-corection only)

[steven at gcc dot gnu dot org]

------- Comment #1 from steven at gcc dot gnu dot org  2010-08-13 07:22 -------
Should use sreal, then?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45273

[Bug middle-end/45273] [4.4/4.5/4.6 Regression] The compiler depends on the host double (-fprofile-corection only)

[jakub at gcc dot gnu dot org]

------- Comment #2 from jakub at gcc dot gnu dot org  2010-08-24 15:42 -------
Well, we don't have sreal_sqrt, and the approximation mcf_sqrt uses is quite
tied to the float representation, while it isn't impossible to convert it, I'd
say it isn't trivial either.  Perhaps we could use mpfr instead.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45273

[Bug middle-end/45273] [4.4/4.5/4.6 Regression] The compiler depends on the host double (-fprofile-corection only)

[rguenth at gcc dot gnu dot org]

------- Comment #3 from rguenth at gcc dot gnu dot org  2010-08-30 15:57 -------
I also see SIGFPEs recently on FDO SPEC 2000.


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rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
           Priority|P3                          |P2
   Last reconfirmed|0000-00-00 00:00:00         |2010-08-30 15:57:37
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45273

[Bug middle-end/45273] [4.4/4.5/4.6 Regression] The compiler depends on the host double (-fprofile-corection only)

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45273

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.4.5                       |4.4.6

[Bug middle-end/45273] [4.4/4.5/4.6 Regression] The compiler depends on the host double (-fprofile-corection only)

[steven at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45273

--- Comment #4 from Steven Bosscher <steven at gcc dot gnu.org> 2011-03-13 00:32:06 UTC ---
Created attachment 23643
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23643
Use mpfr in predict.c instead of sreal, and in mcf.c instead of host double

This completely untested patch shows what I'd like to do: Use mpfr instead of
sreal and host double. Comments on the approach welcome.

[Bug middle-end/45273] [4.4/4.5/4.6 Regression] The compiler depends on the host double (-fprofile-corection only)

[steven at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45273

Steven Bosscher <steven at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |steven at gcc dot gnu.org

--- Comment #5 from Steven Bosscher <steven at gcc dot gnu.org> 2011-03-13 10:55:05 UTC ---
Heh, with my patch (with some further changes) I get failures like this one:
../../trunk/gcc/sel-sched-ir.c:6253:1: error: caller edge frequency 38613 does
not match BB frequency 38610

Excess precision? :-)

[Bug middle-end/45273] [4.4/4.5/4.6 Regression] The compiler depends on the host double (-fprofile-corection only)

[steven at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45273

Steven Bosscher <steven at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #23643|0                           |1
        is obsolete|                            |

--- Comment #6 from Steven Bosscher <steven at gcc dot gnu.org> 2011-03-13 12:39:51 UTC ---
Created attachment 23644
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23644
Use mpfr in predict.c instead of sreal, and in mcf.c instead of host double

Bootstrapped&tested on x86_64-unknown-linux-gnu. Can be queued for GCC 4.7 if
the Powers That Be agree this is the right approach.

The mcf.c parts can be posted separately for GCC 4.6 if necessary, but I
propose to close this big as WONTFIX for older releases.