Big kernel size increase with gcc 3.4

Hello,

these figures speak for themselves:

text data bss dec hex filename

833352   47200   78884  959436   ea3cc linux-2.6.x/vmlinux_gcc331
877420   53212   78884 1009516   f676c linux-2.6.x/vmlinux_gcc34

- target is linux-2.6.0-test2-uc0 for m68knommu (full config available on request);

- same optimization flags: -m5307 -O2 -fno-strict-aliasing -fno-common -fno-builtin -fomit-frame-pointer

- same ColdFire GCC patches were used (I strongly doubt it could be a back-end issue);

- gcc-3.3.1-20030720 VS gcc-3.4-20030806.

I can provide more datails if needed. Could be an inlining issue of course.

Out of curiosity, it seems that the old 2.95.3 could finally be sent to rest now:

  text    data     bss     dec     hex filename
 833352   47200   78884  959436   ea3cc linux-2.6.x/vmlinux_gcc331
 857208   72800   60836  990844   f1e7c linux-2.6.x/vmlinux_gcc295

 // Bernardo Innocenti - Develer S.r.l., R&D dept.
\X/  http://www.develer.com/

Please don't send Word attachments - http://www.gnu.org/philosophy/no-word-attachments.html

You should try -Os if you want to optimize for size.

I did some time ago, and it seems to reduce the code size greatly, but then I noticed some problems with the memory allocator and switched back to -O2 for fear that changing the inlining policy could lead to instability.

I still see those memory allocator problems, so I think I could safely switch back to -Os now... actually I would recommend it for all embedded targets.

 // Bernardo Innocenti - Develer S.r.l., R&D dept.
\X/  http://www.develer.com/

Please don't send Word attachments - http://www.gnu.org/philosophy/no-word-attachments.html

You were both right. With -Os, GCC 3.3.1 and 3.4 perform similarly, with a slight advantage for 3.4 :-)

text data bss dec hex filename

833352   47200   78884  959436   ea3cc vmlinux_gcc331
807140   48036   78884  934060   e40ac vmlinux_gcc331_Os
796264   50560   78884  925708   e200c vmlinux_gcc34_Os

 // Bernardo Innocenti - Develer S.r.l., R&D dept.
\X/  http://www.develer.com/

Please don't send Word attachments - http://www.gnu.org/philosophy/no-word-attachments.html

Could you add -fno-reorder-blocks and report the result?

Toshi