[Bug optimization/11975] New: gcc miscompiles natClassLoader.cc with -fnon-call-exceptions

[tausq at debian dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11975

           Summary: gcc miscompiles natClassLoader.cc with -fnon-call-
                    exceptions
           Product: gcc
           Version: 3.4
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: tausq at debian dot org
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: hppa-unknown-linux
  GCC host triplet: hppa-unknown-linux
GCC target triplet: hppa-unknown-linux

While trying to build libjava for hppa-linux, i ran into a few cases where gcc
built code that segfaults when run. One example is attached -- this code was
extracted from natClassLoader.cc, when built with -fnon-call-exceptions, gcc
emits an insn:

       ldw RT'loaded_classes(%r25),%r25

but r25 is never initialized. It looks like the gcse pass eliminated the
initialization of r25

The complete build command was:
gcc -fno-rtti -fdollars-in-identifiers -Wswitch-enum -fnon-call-exceptions -O2
-g -fPIC -S bug.ii

With -fno-gcse, the code looks like:
        .loc 1 48 0
        addil LT'loaded_classes,%r19
        ldw RT'loaded_classes(%r1),%r1

without -fno-gcse
        .loc 1 48 0
        ldw RT'loaded_classes(%r25),%r25