| Summary: | warn about common variable alignment problems | ||
|---|---|---|---|
| Product: | gcc | Reporter: | Thomas Koenig <Thomas.Koenig> |
| Component: | fortran | Assignee: | Not yet assigned to anyone <unassigned> |
| Status: | RESOLVED FIXED | ||
| Severity: | enhancement | CC: | gcc-bugs |
| Priority: | P2 | Keywords: | diagnostic |
| Version: | 4.0.0 | ||
| Target Milestone: | 4.0.0 | ||
| Host: | Target: | ||
| Build: | Known to work: | ||
| Known to fail: | Last reconfirmed: | 2004-12-02 21:01:49 | |
| Bug Depends on: | |||
| Bug Blocks: | 19292 | ||
Confirmed. This is fixed with the 20050116 snapshot:
$ gfortran common.f
In file common.f:3
common /foo/ c,r
1
Warning: COMMON 'foo' at (1) requires 3 bytes of padding at start
Thomas
|
$ cat common.f program main character*1 c common /foo/ c,r c = 'a' r = 1.2 end $ g77 common.f common.f: In program `main': common.f:3: warning: common /foo/ c,r ^ Initial padding for common block `foo' is 3 bytes at (^) -- consider reorderingmembers, largest-type-size first $ gfortran common.f $ gfortran -v Reading specs from /home/ig25/lib/gcc/i686-pc-linux-gnu/4.0.0/specs Configured with: ../gcc/configure --prefix=/home/ig25 --enable-languages=c,c++,f95 : (reconfigured) ../gcc/configure --prefix=/home/ig25 --with-gcc-version-trigger=/home/ig25/gcc/gcc/version.c --enable-languages=c,c++,f95 --no-create --no-recursion Thread model: posix gcc version 4.0.0 20041129 (experimental) Just about any Fortran compiler warns about this sort of thing (and they should, the performance penalty for this kind of thing can be severe).