[Bug other/14708] description of -ffloat-store in gcc man page incorrect/inaccurate

[vincent at vinc17 dot org]

--- Additional Comments From vincent at vinc17 dot org  2004-12-08 15:13 
---
I'm wrong. gcc 3.4 (from Debian) still has this problem. So, -ffloat-store is
still needed for C compliance.

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14708

[Bug other/14708] description of -ffloat-store in gcc man page incorrect/inaccurate

[vincent at vinc17 dot org]

--- Additional Comments From vincent at vinc17 dot org  2004-11-29 15:35 
---
In Comment 5, I wrote:
> The real problem is that intermediate results in extended precision are not
converted back to double after a cast or an assignment; this is required by the
C standard, whether __STDC_IEC_559__ is defined or not.

This problem has been fixed in gcc 3.4. So, now I think that the -ffloat-store
option should no longer be used: if the user wants the result to be converted
into double precision, he could add a cast to double, which is more portable
than relying on --ffloat-store. Also, note that neither the cast nor the
-ffloat-store option solves the problem of "double rounding" as described here:

  http://www.vinc17.org/research/extended.en.html

IMHO the manual should discourage the use of -ffloat-store.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14708

[Bug other/14708] description of -ffloat-store in gcc man page incorrect/inaccurate

[pinskia at gcc dot gnu dot org]

--- Additional Comments From pinskia at gcc dot gnu dot org  2004-11-29 
14:24 ---
Confirmed.

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   What|Removed |Added

 Status|UNCONFIRMED |NEW
 Ever Confirmed||1
   Last reconfirmed|-00-00 00:00:00 |2004-11-29 14:24:22
   date||


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14708