[LLVMbugs] [Bug 9891] New: static const struct optimized-away incorrectly by llvm-gcc

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=9891

           Summary: static const struct optimized-away incorrectly by
                    llvm-gcc
           Product: new-bugs
           Version: unspecified
          Platform: Macintosh
        OS/Version: MacOS X
            Status: NEW
          Severity: normal
          Priority: P
         Component: new bugs
        AssignedTo: unassignedbugs at nondot.org
        ReportedBy: stash at cpan.org
                CC: llvmbugs at cs.uiuc.edu


Created an attachment (id=6573)
 --> (http://llvm.org/bugs/attachment.cgi?id=6573)
Program that fails to run correctly after compiling with llvm-gcc

An anonymous struct defined as "static const" seems to be optimized-away when
llvm-gcc is given the '-O' flag. I'd expect the attached program to print
something, but it does not.  

The following things seem to restore correct behaviour:
* change "static const" to just "const" (i.e. don't use a static initializer)
* use gcc instead of llvm-gcc
* compile *without* the -O flag (or use -O0)

I saw that clang doesn't currently support static initialization of flexible
members, but the struct in this program isn't a member of anything.

I'm not sure that this is an llvm bug since I'm using Apple's llvm-gcc included
in Xcode 4.0.2.  --version: 

i686-apple-darwin10-llvm-gcc-4.2 (GCC) 4.2.1 (Based on Apple Inc. build 5658)
(LLVM build 2335.9)

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