[Bug target/55036] New: Compiler fails with message "internal compiler error: in reg_save_code, at caller-save.c:158"

["jantlatlik at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55036

             Bug #: 55036
           Summary: Compiler fails with message "internal compiler error:
                    in reg_save_code, at caller-save.c:158"
    Classification: Unclassified
           Product: gcc
           Version: 4.6.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: jantlatlik@gmail.com


Assume the movm insn is the first define_insn pattern in the target md file:
When compiling with the built compiler at least with optimization level 2
(-O2), the compiler will always fail during compile when function calls are
involved.

The following error message occurs:
"internal compiler error: in reg_save_code, at caller-save.c:158"

A short web search lead me to this:
http://old.nabble.com/upgrading-gcc-4.4.0-to-gcc-4.7.0%3Aconfigure%3A-error%3A-cannot-compute-suffix-of-object-files%3A-cannot-compile-td34003613.html

Apparently he could fix it by putting any other define_insn (e.g. nop) right
before the mov insns, so the first mov insn does not get the index 0.
That worked for me as well.

I could not find any documentation about not putting a mov insn pattern at the
beginning of the md file. Therefore I assume it's a bug.