[LLVMdev] weird issue with mem2reg

[Patrick Meredith]

MetaSplit is an anlysis I just finished writing.  It doesn't alter anything,
all it does is build a set of "program instructions".  For some reason even
though if I run it with any other combination of passes I've found, anytime
I run it with mem2reg I get a seg fault in dyn_cast!  Here's output:

Starting program:
/mounts/zion/disks/0/localhome/pmeredit/llvm/tools/Debug/opt -load
../Debug/libmetasplit.so -mem2reg -metasplit < test3.s.bc > out.bc

Program received signal SIGSEGV, Segmentation fault.
0x083b6a22 in llvm::isa_impl_wrap<llvm::Instruction, llvm::Value const,
llvm::Value const>::doit(llvm::Value const&) (Val=@0x894e850)
    at
/mounts/zion/disks/0/localhome/pmeredit/llvm/include/Support/Casting.h:69
69          return isa_impl<To,FromTy>(Val);
(gdb) bt
#0  0x083b6a22 in llvm::isa_impl_wrap<llvm::Instruction, llvm::Value const,
llvm::Value const>::doit(llvm::Value const&) (Val=@0x894e850)
    at
/mounts/zion/disks/0/localhome/pmeredit/llvm/include/Support/Casting.h:69
#1  0x083b69f7 in isa<llvm::Instruction> (Val=@0x894e850) at
/mounts/zion/disks/0/localhome/pmeredit/llvm/include/Support/Casting.h:80
#2  0x083b693f in isa<llvm::Instruction> (Val=@0x894e850) at
/mounts/zion/disks/0/localhome/pmeredit/llvm/include/Support/Casting.h:90
#3  0x083b6673 in isa<llvm::Instruction> (Val=0x894e850) at
/mounts/zion/disks/0/localhome/pmeredit/llvm/include/Support/Casting.h:99
#4  0x083b6379 in isa<llvm::Instruction, const llvm::Value*>
(Val=@0xbf8000c0) at
/mounts/zion/disks/0/localhome/pmeredit/llvm/include/Support/Casting.h:114
#5  0x083b608f in llvm::CallInst::classof(llvm::Value const*) (V=0x894e850)
at /mounts/zion/disks/0/localhome/pmeredit/llvm/include/llvm/iOther.h:110
#6  0x08499213 in isa_impl<llvm::CallInst, llvm::Value> (Val=@0x894e850) at
/mounts/zion/disks/0/localhome/pmeredit/llvm/include/Support/Casting.h:52
#7  0x08499157 in llvm::isa_impl_wrap<llvm::CallInst, llvm::Value const,
llvm::Value const>::doit(llvm::Value const&) (Val=@0x894e850)
    at
/mounts/zion/disks/0/localhome/pmeredit/llvm/include/Support/Casting.h:69
#8  0x08498ea7 in isa<llvm::CallInst> (Val=@0x894e850) at
/mounts/zion/disks/0/localhome/pmeredit/llvm/include/Support/Casting.h:80
#9  0x08498b79 in isa<llvm::CallInst> (Val=0x894e850) at
/mounts/zion/disks/0/localhome/pmeredit/llvm/include/Support/Casting.h:99
#10 0x4001d1f6 in isa<llvm::CallInst> (Val=@0xbf800170) at
/localhome/pmeredit/llvm/include/Support/Casting.h:90
#11 0x4001cfb3 in llvm::isa_impl_wrap<llvm::CallInst, llvm::Use const,
llvm::Value*>::doit(llvm::Use const&) (Val=@0xbf800200)
    at /localhome/pmeredit/llvm/include/Support/Casting.h:60
#12 0x4001ca1c in isa<llvm::CallInst> (Val=@0xbf800200) at
/localhome/pmeredit/llvm/include/Support/Casting.h:80
#13 0x4001c1ca in isa<llvm::CallInst, llvm::Use> (Val=@0xbf800200) at
/localhome/pmeredit/llvm/include/Support/Casting.h:114
#14 0x4001baaa in dyn_cast<llvm::CallInst, llvm::Use> (Val={Val = 0x894e850,
U = 0x8917e48, Prev = 0x895a240, Next = 0x894e880})
    at /localhome/pmeredit/llvm/include/Support/Casting.h:223
#15 0x4001af72 in (anonymous
namespace)::MetaSplit::handleProgramUses(llvm::Value*) (this=0x893e998,
V=0x8917e48) at MetaSplit.cpp:79
#16 0x4001b049 in (anonymous
namespace)::MetaSplit::handleProgramUses(llvm::Value*) (this=0x893e998,
V=0x895ff40) at MetaSplit.cpp:88
#17 0x4001b049 in (anonymous
namespace)::MetaSplit::handleProgramUses(llvm::Value*) (this=0x893e998,
V=0x8930610) at MetaSplit.cpp:88
#18 0x4001b049 in (anonymous
namespace)::MetaSplit::handleProgramUses(llvm::Value*) (this=0x893e998,
V=0x89609a8) at MetaSplit.cpp:88
#19 0x4001b049 in (anonymous
namespace)::MetaSplit::handleProgramUses(llvm::Value*) (this=0x893e998,
V=0x8930610) at MetaSplit.cpp:88
#20 0x4001b049 in (anonymous
namespace)::MetaSplit::handleProgramUses(llvm::Value*) (this=0x893e998,
V=0x89609a8) at MetaSplit.cpp:88
#21 0x4001b049 in (anonymous
namespace)::MetaSplit::handleProgramUses(llvm::Value*) (this=0x893e998,
V=0x8930610) at MetaSplit.cpp:88
#22 0x4001b049 in (anonymous
namespace)::MetaSplit::handleProgramUses(llvm::Value*) (this=0x893e998,
V=0x89609a8) at MetaSplit.cpp:88
#23 0x4001b049 in (anonymous
namespace)::MetaSplit::handleProgramUses(llvm::Value*) (this=0x893e998,
V=0x8930610) at MetaSplit.cpp:88
#24 0x4001b049 in (anonymous
namespace)::MetaSplit::handleProgramUses(llvm::Value*) (this=0x893e998,
V=0x89609a8) at MetaSplit.cpp:88
#25 0x4001b049 in (anonymous
namespace)::MetaSplit::handleProgramUses(llvm::Value*) (this=0x893e998,
V=0x8930610) at MetaSplit.cpp:88
#26 0x4001b049 in (anonymous
namespace)::MetaSplit::handleProgramUses(llvm::Value*) (this=0x893e998,
V=0x89609a8) at MetaSplit.cpp:88
#27 0x4001b049 in (anonymous
namespace)::MetaSplit::handleProgramUses(llvm::Value*) (this=0x893e998,
V=0x8930610) at MetaSplit.cpp:88
#28 0x4001b049 in (anonymous
namespace)::MetaSplit::handleProgramUses(llvm::Value*) (this=0x893e998,
V=0x89609a8) at MetaSplit.cpp:88
#29 0x4001b049 in (anonymous
namespace)::MetaSplit::handleProgramUses(llvm::Value*) (this=0x893e998,
V=0x8930610) at MetaSplit.cpp:88