[LLVMbugs] [Bug 3667] New: instcombine divide by zero on array with zero-length element type

[bugzilla-daemon at cs.uiuc.edu]

http://llvm.org/bugs/show_bug.cgi?id=3667

           Summary: instcombine divide by zero on array with zero-length
                    element type
           Product: new-bugs
           Version: unspecified
          Platform: Other
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: new bugs
        AssignedTo: unassignedbugs at nondot.org
        ReportedBy: baldrick at free.fr
                CC: llvmbugs at cs.uiuc.edu


Created an attachment (id=2608)
 --> (http://llvm.org/bugs/attachment.cgi?id=2608)
testcase .ll

$ opt -instcombine -disable-output divide_by_zero.bc
0   opt       0x0000000000d956b2
1   opt       0x0000000000d95a0c
2   libc.so.6 0x00007f2605387040
3   opt       0x0000000000a21c98
4   opt       0x0000000000a223bf
5   opt       0x0000000000a2a8af
6   opt       0x0000000000a2b27a
7   opt       0x0000000000a2b582
8   opt       0x0000000000cefb81
llvm::FPPassManager::runOnFunction(llvm::Function&) + 239
9   opt       0x0000000000cefce4
llvm::FPPassManager::runOnModule(llvm::Module&) + 82
10  opt       0x0000000000ceefb7
llvm::MPPassManager::runOnModule(llvm::Module&) + 189
11  opt       0x0000000000cf05c2 llvm::PassManagerImpl::run(llvm::Module&) +
116
12  opt       0x0000000000cf0625 llvm::PassManager::run(llvm::Module&) + 33
13  opt       0x00000000008f738c main + 4192
14  libc.so.6 0x00007f26053725a6 __libc_start_main + 230
15  opt       0x00000000008d1359
Floating point exception (core dumped)

The problem is that ArrayEltSize is zero here:

10836           // If the index will be to exactly the right offset with the
scale taken
10837           // out, perform the transformation. Note, we don't know whether
Scale is
10838           // signed or not. We'll use unsigned version of division/modulo
10839           // operation after making sure Scale doesn't have the sign bit
set.
10840           if (Scale && Scale->getSExtValue() >= 0LL &&
10841               Scale->getZExtValue() % ArrayEltSize == 0) {


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