[LLVMdev] possible regression regarding bitcasts?

[Nick Lewycky]

This isn't due to the bitcasts, it's crashing trying to verify the use of
the memcpy intrinsic. Please file a bug report so we can track this, and
please include your excellent testcase!

Nick

On 8 June 2010 10:10, Bagel <bagel99 at gmail.com> wrote:

> The following code works on 2.7, but causes an assertion on recent
> snapshots.
> Has something changed regarding bitcasts that makes this illegal?
>
> The code is:
>
> target datalayout =
> "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:32"
> target triple = "x86-unknown-unknown"
> @aa = global [32 x i8] zeroinitializer, align 1
> @bb = global [16 x i8] zeroinitializer, align 1
> define void @x() nounwind {
> L.0:
>        %0 = getelementptr [32 x i8]* @aa, i32 0, i32 4
>        %1 = bitcast i8* %0 to [16 x i8]*
>        %2 = bitcast [16 x i8]* %1 to [0 x i8]*
>        %3 = getelementptr [16 x i8]* @bb
>        %4 = bitcast [16 x i8]* %3 to [0 x i8]*
>        call void @llvm.memcpy.i32([0 x i8]* %2, [0 x i8]* %4, i32 16, i32
> 1)
>        br label %return
> return:
>        ret void
> }
> declare void @llvm.memcpy.i32([0 x i8]*, [0 x i8]*, i32, i32) nounwind
>
> The assertion is:
> Unknown type!
> UNREACHABLE executed at ValueTypes.cpp:190!
> 0  opt             0x000000000081cf8f
> 1  opt             0x000000000081effa
> 2  libpthread.so.0 0x0000003961a0f0f0
> 3  libc.so.6       0x0000003960e326d5 gsignal + 53
> 4  libc.so.6       0x0000003960e33eb5 abort + 373
> 5  opt             0x0000000000800e14 llvm::llvm_unreachable_internal(char
> const*, char const*, unsigned int) + 356
> 6  opt             0x00000000007c8733 llvm::EVT::getEVT(llvm::Type const*,
> bool) + 979
> 7  opt             0x00000000007ccff1
> 8  opt             0x00000000007cd446
> 9  opt             0x00000000007d56b7
> 10 opt             0x00000000007d6826
> 11 opt             0x00000000007b223d
> llvm::FPPassManager::runOnFunction(llvm::Function&) + 637
> 12 opt             0x00000000007b233b
> llvm::FPPassManager::runOnModule(llvm::Module&) + 75
> 13 opt             0x00000000007b1d41
> llvm::MPPassManager::runOnModule(llvm::Module&) + 497
> 14 opt             0x00000000007b1eb7
> llvm::PassManagerImpl::run(llvm::Module&)
> + 167
> 15 opt             0x00000000004a1a02 main + 2642
> 16 libc.so.6       0x0000003960e1eb1d __libc_start_main + 253
> 17 opt             0x0000000000497639
> Stack dump:
> 0.      Program arguments: /home/bgl/work/llvm-work/Release/bin/opt
> -std-compile-opts -o - t322.ll
> 1.      Running pass 'Function Pass Manager' on module 't322.ll'.
> 2.      Running pass 'Module Verifier' on function '@x'
>
> Any ideas?
> Thanks.
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