[Bug debug/48928] New: [4.7 Regression] ICE: in decimal_to_decnumber, at dfp.c:113 with -O -g and decimal float

[Bug debug/48928] New: [4.7 Regression] ICE: in decimal_to_decnumber, at dfp.c:113 with -O -g and decimal float

[zsojka at seznam dot cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48928

           Summary: [4.7 Regression] ICE: in decimal_to_decnumber, at
                    dfp.c:113 with -O -g and decimal float
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: zsojka@seznam.cz
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu


Created attachment 24207
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24207
reduced testcase

Compiler output:
$ gcc -O -g testcase.c
testcase.c: In function 'foo':
testcase.c:7:1: internal compiler error: in decimal_to_decnumber, at dfp.c:113
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

Tested revisions:
r173545 - crash
4.6 r173059 - OK

[Bug debug/48928] [4.7 Regression] ICE: in decimal_to_decnumber, at dfp.c:113 with -O -g and decimal float

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48928

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2011.05.08 13:40:54
                 CC|                            |jakub at redhat dot com
   Target Milestone|---                         |4.7.0
     Ever Confirmed|0                           |1

--- Comment #1 from H.J. Lu <hjl.tools at gmail dot com> 2011-05-08 13:40:54 UTC ---
It is cause by revision 173210:

http://gcc.gnu.org/ml/gcc-cvs/2011-04/msg01406.html

[Bug debug/48928] [4.7 Regression] ICE: in decimal_to_decnumber, at dfp.c:113 with -O -g and decimal float

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48928

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
         AssignedTo|unassigned at gcc dot       |jakub at gcc dot gnu.org
                   |gnu.org                     |

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-05-09 09:32:23 UTC ---
Created attachment 24211
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24211
gcc47-pr48928.patch

Ugh, dfp is complete mess, in many places in the folder, middle-end and
optimizers dconst{1,2,m1,half} are used even for decimal types/modes, but those
real formats are binary, not decimal.  The following patch just accepts the
status quo and handles those 4 standard constants specially instead of ICEing
on them.

[Bug debug/48928] [4.7 Regression] ICE: in decimal_to_decnumber, at dfp.c:113 with -O -g and decimal float

[joseph at codesourcery dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48928

--- Comment #3 from joseph at codesourcery dot com <joseph at codesourcery dot com> 2011-05-09 09:56:56 UTC ---
On Mon, 9 May 2011, jakub at gcc dot gnu.org wrote:

> Ugh, dfp is complete mess, in many places in the folder, middle-end and
> optimizers dconst{1,2,m1,half} are used even for decimal types/modes, but those
> real formats are binary, not decimal.  The following patch just accepts the
> status quo and handles those 4 standard constants specially instead of ICEing
> on them.

There should probably be a separate PR filed for the underlying problem of 
using those values for decimal floating-point - given that all these 
constants have multiple decimal floating-point representations (with 
different quantum exponents), a decimal floating-point expert ought to 
look at all the uses to figure out what is actually correct in terms of 
getting the right quantum for results, and I doubt the code gets this 
right at present.

[Bug debug/48928] [4.7 Regression] ICE: in decimal_to_decnumber, at dfp.c:113 with -O -g and decimal float

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48928

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-05-10 06:05:23 UTC ---
Author: jakub
Date: Tue May 10 06:05:20 2011
New Revision: 173606

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=173606
Log:
    PR debug/48928
    * dfp.c (decimal_to_decnumber): Handle conversion from
    dconst{1,2,m1,half}.

    * gcc.dg/dfp/pr48928.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/dfp/pr48928.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/dfp.c
    trunk/gcc/testsuite/ChangeLog

[Bug debug/48928] [4.7 Regression] ICE: in decimal_to_decnumber, at dfp.c:113 with -O -g and decimal float

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48928

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-05-10 06:20:37 UTC ---
Fixed.