[Bug c/61578] New: Code size increase for ARM thumb compared to 4.8.x when compiling with -Os

[fredrik.hederstierna@securitas-direct.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61578

            Bug ID: 61578
           Summary: Code size increase for ARM thumb compared to 4.8.x
                    when compiling with -Os
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: fredrik.hederstierna@securitas-direct.com

We have problems when trying to switch from GCC 4.8.3 to GCC 4.9.0 (arm-eabi
thumb1 for arm966e-s core) due to significant code size increase (1-2%).

I attach our toolchain build scripts and two small example programs, though I'm
not fully convinced that these examples fully catch the issue.
Although the examples show increase +4.81% and +2% growth, though the examples
are slightly constructed.

First I suspected it was related to Bug 59535, since the code size decrease
significantly when compiling without LRA (-mno-lra), though still it does not
make the full picture, since still the codes size is ~1% bigger then GCC 4.8.3.

We also tried with and without LTO, but it does not solve our problem either.
See attached example.
Build with 'make' and compare with 'make compare'.

Thanks and Best Regards,
/Fredrik